Mineral composition

ABSTRACT

A roofing shingle that contains a roofing granules. The roofing granules contain at least about 95 weight percent of calcium carbonate with a hardgrove grindability index of less than about 70, and from about 0.1 to about 1.0 weight percent of a pigmented material; the pigmented material contains from about 10 to about 35 weight percent of pigment and from about 90 to about 65 weight percent of a resin; and the roofing granules are coated with an amine antistrip agent.

CROSS-REFERENCE TO RELATED PATENT APPLICATION

This patent application is a continuation-in-part of applicants' patentapplication Ser. No. 11/999,205, filed on Dec. 4, 2007 now U.S. Pat. No.7,651,559, which in turn was a continuation-in-part of patentapplication Ser. No. 11/638,618, filed on Dec. 13, 2006 now abandoned,which in turn was a continuation-in-part of patent application Ser. No.11/266,833, filed on Nov. 4, 2005 now abandoned. The entire disclosureof each of such patent applications is hereby incorporated by referenceinto this specification.

FIELD OF THE INVENTION

A roofing shingle comprised of a mineral composition, wherein saidmineral composition is comprised of at least 90 weight percent ofroofing granules that comprise at least 95 weight percent of calciumcarbonate with a hardgrove grindability index of less than about 70.

BACKGROUND OF THE INVENTION

Roofing shingles are comprised of a headlap portion and a butt portion;granules are often used in both of such portions. Reference may be had,e.g., to U.S. Pat. No. 3,921,358 (a composite asphalt-impregnated feltroofing shingle comprising a rectangular sheet having a headlap portionand a butt portion), U.S. Pat. No. 4,717,614 (a shingle whose headlapportion is coated with a layer of asphaltic material), U.S. Pat. No.4,900,589 (a process for applying granules to a moving sheet having aheadlap area and a butt area for making a shingle roofing product), U.S.Pat. No. 6,358,305 (a process of preparing a darkened headlap for aroofing shingle), and the like. The entire disclosure of each of theseUnited States patents is hereby incorporated by reference into thisspecification.

U.S. Pat. No. 6,358,305 of Ingo B. Joedicke discloses coated headlapgranules that may comprise “ . . . limestone, rock, greenstone,nephylene syenite, gravel, slate, ganister, quartzite, and greystone . .. ” granules (see lines 30-34 of column 4). The patent discloses “Thegranules are typically in a size range between about 10 to 35 mesh, i.e.particle sizes which will pass through an 8 mesh screen but retained ona 35 mesh screen . . . ” (see lines 34-37 of column 4).

In the Examples of U.S. Pat. No. 6,358,305, an experiment is describedin which “ . . . dedusted headlap-grade crushed rock aggregate . . . ”was used. However, Joedicke discloses that the aggregate may also bemade from “ . . . limestone, . . . greenstone, nephylene syenite, gravelslate, ganister, quartzite, and greystone . . . ” (see lines 30 to 34 ofcolumn 4 of such patent); but he does not disclose, e.g., how one wouldprepare a “dedusted, headlap-grade” limestone material.

When a headlap material is made from limestone using the processdisclosed in the Joedicke patent, the adhesion properties the headlapgranules so produced are not satisfactory.

It is an object of this invention to provide a headlap materialcomprised of at least 95 weight percent of calcium carbonate that hasacceptable adhesion properties.

It is another object of this invention to provide a bituminous roofingproduct with acceptable properties that is comprised of headlap granulesthat contain at least about 95 weight percent of calcium carbonate.

SUMMARY OF THE INVENTION

In accordance with this invention, there is provided a roofing shinglecomprised of a mineral composition. The mineral composition is comprisedof at least 90 weight percent of roofing granules, wherein said roofinggranules are comprised of at least about 95 weight percent of calciumcarbonate with a hardgrove grindability index of less than about 70, andfrom about 0.1 to about 1.0 weight percent of a pigmented material,wherein said pigmented material is comprised of from about 10 to about35 weight percent of pigment and from about 90 to about 65 weightpercent of a resin, and wherein said roofing granules are comprised ofamine antistrip agent, wherein at least 80 weight percent of saidroofing granules have sizes in the range of from about 600 to about 1400microns, wherein less than about 4 weight percent of said roofinggranules are smaller than 250 microns, wherein said roofing granules arecomprised of at least 95 weight percent of particles smaller than 1700microns, wherein said roofing granules are comprised of at least 30weight percent of particles smaller than 850 microns, and wherein saidroofing granules are comprised of at least 3 weight percent of particlessmaller than 600 microns.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described by reference to the following drawings,in which like numerals refer to like elements, and wherein:

FIG. 1 is a flow diagram of one preferred process of the invention;

FIG. 2 is a schematic of a test apparatus for determining thehydrophobicity of coated particles;

FIG. 3 is a flow diagram of a process for coating headlap granules withresin and pigment;

FIG. 4 is a schematic diagram of a preferred process of the invention;and

FIG. 5 is a schematic diagram of a shingle comprised of headlapparticles.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Roofing granules are well known to those skilled in the art. Referencemay be had, e.g., to U.S. Pat. No. 3,884,706 (algicidal roofinggranules), U.S. Pat. No. 4,092,441 (roofing granule treatment by coatingwith a metallic algicide), U.S. Pat. No. 4,359,505 (light coloredroofing granules), U.S. Pat. No. 5,380,552 (method of improving adhesionbetween roofing granules and asphalt-based roofing materials), U.S. Pat.No. 6,156,289 (iron based roofing granules and method of coloring thesame), U.S. Pat. No. 6,607,781 (roofing granules with a decorative metalappearance), U.S. Pat. No. 7,060,658 (roofing granules), and the like.The entire disclosure of each of these United States patents is herebyincorporated by reference into this specification.

Roofing granules made from coal slag have excellent adhesion properties.However, some have expressed concerns about the safety of coal slag (ingeneral) and of roofing granules made from coal slag. It would bedesirable to be able to make roofing granules with good adhesionproperties from a more “environmentally friendly” material than coalslag.

Limestone is a substantially more “environmentally friendly” materialthan coal slag. Thus, e.g., limestone is often fed to chickens as a feedsupplement. However, the adhesion properties of limestone granules areoften not deemed to be adequate for use in roofing shingles.

Adhesion Properties and Adhesion Testing of Roofing Granules

The adhesion properties of roofing granules is extensively discussed inU.S. Pat. No. 5,380,552 (“Method of improving adhesion between roofinggranules and asphalt-based material”), the entire disclosure of which ishereby incorporated by reference into this specification.

At lines 37-48 of U.S. Pat. No. 5,380,552, it is disclosed that “Theexterior, outer, or exposed surface of asphalt roofing systems andproducts is generally provided with a covering of granular material orroofing granules embedded within the coating asphalt. The granularmaterial generally protects the underlying asphalt coating from damagedue to exposure to light, in particular ultraviolet (UV) light. That is,the granules reflect light and protect the asphalt from deterioration byphotodegradation. In addition, such granular material improves fireresistance and weathering characteristics. Further, colors or mixturesof colors of granular material may be selected for aesthetics.”

The adherence of the roofing granules to the roofing product isdiscussed at lines 56-63 of column 1 of U.S. Pat. No. 5,380,552, whereinit is disclosed that: “Good adherence of the roofing granules to theroofing product is beneficial. Loss of granules reduces the life of theroof, since it is associated with acceleration of photodegradation ofthe asphalt. In addition, the aesthetics of the roofing system may becompromised if granules are lost. Further, reduction of granule lossduring installation improves safety conditions on the roof.”

Granule loss due to abrasion is discussed at the last paragraph ofcolumn 1 of U.S. Pat. No. 5,380,552, wherein it is disclosed that,“Granule loss can also occur due to physical abrasion of the granularsurface. This may occur any time a person walks on an installed roof formaintenance, during installation of the roofing surface or by suchenvironmental conditions as tree branches rubbing on the granularsurface and the physical contact of rain or hail with the roofingsurface.”

The benefits of reducing such granule loss are discussed at lines 34-37of column 4 of U.S. Pat. No. 5,380,552, wherein it is disclosed that,“Improved granule retention increases the useful life of the roofingsystem by inhibiting exposure of the asphalt layer to ultraviolet lightand thus inhibiting photodegradation of the coating asphalt.”

At lines 53 (of column 4) to 10 (of column 5), the substrate used inmaking roofing shingles is discussed. It is disclosed that, “A varietyof materials may be utilized as the substrate for the roofing materials.In general, preferred materials comprise a non-woven matting of eitherfiberglass or cellulose fibers. Fiberglass matting is used most widelyin the asphalt roofing products industry and is a typical and preferredsubstrate for use with methods and in products according to the presentinvention. Cellulose matting, sometimes referred to as organic mattingor rag felt may also be utilized. Fiberglass matting is commerciallyavailable from Owens-Corning Fiberglass Corporation, Toledo, Ohio andManville Roofing Systems, Denver, Colo. These commercially-availablesubstrates are utilized in preferred embodiments of the presentinvention. It is recognized that any fiberglass mat with similarphysical properties could be incorporated into the process of thepresent invention with satisfactory results. Generally, the fiberglassmatting is manufactured from a silicate glass fiber blown in a non-wovenpattern in streams of about 30-200 micrometers in diameter with theresultant mat approximately 1-5 millimeters in thickness. Cellulose felt(dry felt) is typically made from various combinations of rag, wood andother cellulose fibers or cellulose-containing fibers blended inappropriate proportions to provide the desirable strength, absorptioncapacity and flexibility.”

At lines 13-39 of column 5 of U.S. Pat. No. 5,380,552, the asphalt usedin making roofing flux is disclosed. In this section of such patent, itis stated that: “Roofing asphalt, sometimes termed “asphalt flux”, is apetroleum based fluid comprising a mixture of bituminous materials. Inthe manufacture of roofing it is generally desirable to soak theabsorbent felt or fiberglass mat until it is impregnated or saturated tothe greatest possible extent with a ‘saturant’ asphalt, thus the asphaltshould be appropriate for this purpose. Saturant asphalt is high in oilyconstituents which provide waterproofing and other preservatives.Substrates saturated with saturant asphalt are generally sealed on bothsides by application of a hard or more viscous ‘coating asphalt’ whichitself is protected by the covering of mineral granules. In the case offiberglass mat based asphalt roofing products, it is well understoodthat the coating asphalt can be applied directly to the unsaturatedfiberglass mat. The asphalts used for saturant asphalt and the coatingasphalt are prepared by processing the asphalt flux in such a way as tomodify the temperature at which it will soften. The softening point ofsaturant asphalt varies from about 37° C. to about 72° C., whereas thesoftening point of desirable coating asphalt runs as high as about 127°C. The softening temperature may be modified for application to roofsystems in varying climates. In general, conventional, commerciallyavailable, asphalt systems may be utilized in applications of thepresent invention.”

A conventional means of making roofing shingles is discussed at columns7-9 of U.S. Pat. No. 5,380,552. In the paragraph beginning at line 46 ofcolumn 7 of such patent, it is disclosed that, “A schematic generallyillustrating preparation of roofing shingles according to the presentinvention is illustrated in FIG. 1. Except for addition of adhesives asdescribed, and modifications to accommodate addition of adhesives asdescribed, the system in FIG. 1 is generally as presented in U.S. Pat.No. 4,352,837 . . . , incorporated herein by reference. In operation, aroll of dry felt or bonded fiberglass mat 12, (the substrate) in sheetform, is installed on a feed roll 13 and unwound onto a dry looper 14.The dry looper 14 acts as a reservoir of mat material that can be drawnupon during the manufacturing operation to inhibit stoppages which mightotherwise occur when new or additional rolls are fed into the system.Dry felt, or mat 12, is subjected to a hot asphalt saturating process,indicated generally at 15, after it passes through dry looper 14. Thepurpose of the asphalt saturating process 15 is to eliminate moistureand to fill the intervening spaces of the fibers of the substrate 12 ascompletely as possible. The saturating process is conducted in asaturation tank 16 in which saturating asphalt is contained. Sufficientheat is added to maintain the saturant asphalt in saturation tank 16 asa flowable liquid, typically at application temperatures of at leastabout 70° C.”

In the paragraph beginning at line 3 of column 8 of U.S. Pat. No.5,380,552, it is disclosed that: “Following saturation tank 16, thesaturated web 17 is passed through wet looper 18 whereat it is cooledand shrunk, permitting excess asphalt material to be further drawn intothe substrate. The mat 12, after saturation with saturating asphalt intank 16, is next passed through looper 18 and is then directed intocoating area 20, for uniform coating with a coating asphalt, to the topand bottom of the mat. Coating area 20 contains a material reservoir 22and an applicator with a distributor nozzle 23, which are operated toapply the asphalt coating material to the top surface of the mat. Excesscoating material flows over the sides of the substrate and into a pan(not shown) from which it is picked up by adjustable rollers 25 forapplication to the bottom of the web, in a uniform layer. If, the mat 12comprises a fiberglass mat, it is well accepted in the industry that thecoating asphalt can be directly applied to an unsaturated fiberglassmat, although it may be saturated first. Thus, the above-describedprocess can be modified by feeding the fiberglass mat 12 directly fromdry looper 14 to the coating area 20. At station 30, an adhesivereservoir 31 and applicator with distributor nozzle 32 are shown. Thehot-melt adhesive is contained within adhesive reservoir 31 and isdistributed to the upper surface of asphalt-coated web 33 by distributornozzle 32. The adhesive may be applied in a variety of patterns andmanners. In general, satisfactory results are obtained if the adhesiveis applied in thin streams on the order of about 100-200 micrometers indiameter, for example with a blown-fiber adhesive spray gun such as thatmanufactured by PAM Fastening Technology, Model PAM 500KS. The thinstreams may be applied in a random pattern or in other patterns. Ingeneral, for some improvement all that is required is that an effectiveamount of adhesive be applied to the asphalt-coated web 33 upper surfaceto which granular material is eventually applied. By the term ‘effectiveamount’, in this context, it is meant that an amount of adhesive isapplied such that with respect to loss of granular material due tomoisture attack or deterioration, the resulting product is improved. Inaddition, in many applications such an amount of adhesive will alsoimprove dry adhesion. Hereinbelow, a ‘wet rub test’ and a ‘dry rub test’are described, by which improvement can be evaluated. The dry rub testis conducted in accordance with ASTM Standard Test D 4977, and thisstandard test is also used in the present invention to determine thegrams of granules lost.

In the paragraph beginning at line 49 of column 8 of U.S. Pat. No.5,380,552, it is disclosed that: “Preferably the adhesive is distributedin thin streams of about 100-200 micrometers diameter until at leastabout 25% and more preferably 50-75% of the upper surface ofasphalt-coated web 33 is covered thereby. Preferably, the adhesive isapplied while the coating asphalt is still hot, i.e. on the order of atleast 170° C. (340° F.). Still referring to FIG. 1, roofing granules arecontained within hopper or blender 24. They are applied to the uppersurface of adhesive-coated web 43 by gravity feed through granuledistributor 42. Excess granules may be picked up by a mechanismgenerally indicated at spill area 46. In addition, the underside 44 ofweb 43 may be coated with talc, mica or other suitable materials whichare applied by a distributor 48. In order to obtain proper adhesion ofthe granules, the sheet granules are subject to controlled pressure bycompression rollers or drums 51 which force the granules into theasphaltic coating material (and adhesive) a predetermined depth. Coolingmay be added to these drums or rollers to cool the hot asphalt as thegranules are pressed or embedded therein.”

In the paragraph beginning at line 3 of column 9 of U.S. Pat. No.5,380,552, it is disclosed that: “The web with granules embeddedtherein, 52, then travels through tension roller area 53 which assistsin feeding the web material through the previously-disclosed process.The web material 52, with the granules embedded therein, is then fed toa finished or cooling looper 50. The primary function of this looper isto cool the sheet down to a point where it can be cut and packed withoutdanger to the material. Subsequent to the cooling looper 50, the sheetmay be fed to a roll roofing winder 54. Here the sheet is wound on amandrel which measures the length of the material as it turns. Whensufficient material has accumulated it is cut off, removed from themandrel and passed on for wrapping. Alternatively, the sheet leaving thecooling looper 50 may be fed to a shingle cutter 56. It will beunderstood that the finished sheet or web may be cut to desired shapesor sizes and it may be modified, for example, by the addition of liners,application adhesives, or other modifications. The cut shapes or sizesare transferred to a stacking/packing area 58. The type of processingdescribed above is well-known in the manufacturing of shingles or otherroof materials, for example, as described in U.S. Pat. No. 4,352,837,which is incorporated herein by reference.”

A “Dry Rub Test” for determining the extent of adherence of the roofinggranules is described at lines 12-46 of column 10 of U.S. Pat. No.5,380,552. ASTM standard test D 4977-89 was used for the “Dry Rub Test”used in U.S. Pat. No. 5,380,837. ASTM test D 4977-03 is also used forthe “Dry Rub Test” described in this specification.

As is disclosed at lines 12-46 of column 10 of U.S. Pat. No. 5,380,552,“The dry rub test is a standard test method for the determination ofgranular adhesion to mineral-surfaced roofing under conditions ofabrasion. The procedure is described in ASTM standard D 4977-89,incorporated herein by reference. Dry rub tests conducted to evaluategranular adhesion in products according to the present invention, wereconducted in compliance with this standard. In general, a brush with 22holes, each containing bristles made of 0.012 inch diameter temperedsteel wire (40 wires per hole, set with epoxy) was used to abrade thegranular surface of a specimen of mineral-surfaced roofing. The adhesionis assessed by weighing the amounts of granules that are displaced andbecome loose as a result of the abrasion test. The testing apparatus isa machine designed to cycle a test brush back and forth (horizontally)across a specimen at a rate of 50 cycles in a period of about 60-70seconds while the brush assembly rests on the specimen with a downwardmass of 5 pounds±¼ ounce with a stroke link of 6±¼ inch. The testingmachine used is available commercially, as the 3M Granule Embedding TestMachine and Abrasion Test Brushes, Minnesota Mining & Manufacturing,Inc., St. Paul, Minn. A minimum of two 2-inch by 9-inch specimens wereutilized for each test, and any loose granules were removed from thespecimen with gentle tapping. Each specimen was then weighed and themass was recorded. The specimen was then clamped to the test machine andthe brush was placed in contact with the specimen (with activation ofthe machine so that the specimen was abraded 50 complete cycles, thebrush traveling parallel to the long axis of the specimen). The specimenwas then removed and weighed; the loss in mass then being calculated.”

It is preferred to determine the adhesion properties of the roofinggranules by a procedure in which the granules are incorporated into aroofing shingle and the shingle is tested in accordance with ASTM4977-03.

The test samples used to determine the adhesive characteristics of thecoated granule particles are constructed using a petroleum based roofingasphalt which has been oxidized by blowing with air at a temperature ofapproximately 500° Fahrenheit, with a final Ring & Ball Softening Pointof between 195° F. and 215° F. as determined by ASTM D 36, and a NeedlePenetration of between 17 dmm and 23 dmm @ 77° F., as determined by ASTMD 5, this material being typically referred to in the trade as “AsphaltShingle Coating.”

A commercially available bonded non-woven glass roofing fabric with adry weight of approximately 92-95 grams/m³, consisting of sizedindividual “E” Glass filaments of 15.25-16.5 microns in diameter (“M”fiber) and from 0.75-1.25 inches in length, which are randomly orientedand bonded with a modified urea-formaldehyde resin binder, which hasbeen applied to a level of 20% (dry weight), is coated on each side andsaturated with a roofing asphalt compound consisting of Asphalt ShingleCoating containing at least 65% of a mineral filler such as limestone orstone dust, such compound typically referred to in the trade as “FilledAsphalt Coating.” The asphalt coated sheet is allowed to cool to roomtemperature.

The asphalt coated sheet is conditioned, preferably in an oven at 150degrees Fahrenheit, for 30 minutes. After conditioning, samples ofgranule particles produced in the process depicted in FIG. 1 are appliedto the top surface of the warm sheet by gravity feed, and the granuleparticles are roll pressed into the sheet. The finished sheet is allowedto cool to room temperature and is then cut into 2 inch by 9 inch samplespecimens for further testing under ASTM D 4977-03. All loose granuleparticles are removed from the samples by gentle tapping of the specimen

At least two sample specimens are cut for each trial, with the longdimension of the specimen in the machine direction. Specimens areconditioned at room temperature of 23° C. plus or minus 2° C. (73.4° F.plus or minus 3.6° F.) for at least 30 minutes before testing. Granuleabrasion tests are done using a Granule Test Apparatus as described inASTM Procedure D 4977-03. All loose granules are removed from thespecimens by gentle tapping of the sample. Each specimen is weighed tothe nearest 0.01 grams and a record is made of the initial weight of thespecimen. The specimen is centered in the sample holder of the TestApparatus with the mineral surface facing up and the long axis of thespecimen aligned with the brush stroke of the Test Apparatus. The TestApparatus is activated such that the specimen is abraded 50 completecycles, each cycle consisting of a forward stroke and a backstroke, withthe brush travel remaining parallel to the long axis of the specimen.The specimen is removed from the sample holder and any loose granulesare removed from the sheet by gently tapping the sample. The specimen isweighed to the nearest 0.01 grams and a record is made of the finalweight of the specimen. The difference in weights for multiple samplesof the same specimen are calculated and averaged to determine theaverage granule loss by abrasion.

In the remainder of this specification, applicants will discuss theirprocess for preparing the roofing granules of their invention with goodadherence properties, and, in certain embodiments, with specifiedtranslucency and/or color properties.

Preparation of Calcium Carbonate Containing Roofing Granules

In this portion of the specification, applicants will discuss how theyprepare their preferred calcium-carbonate containing roofing granules.

FIG. 1 is a flow diagram of a preferred process 10 for preparing somepreferred limestone granules of this invention. In step 12 of thisprocess, the limestone is mined by conventional means. The limestone somined preferably contains at least about 50 weight percent of calciumcarbonate.

Limestone, processes for mining it, processes for treating it, methodsof using it, and compositions containing it are well known to thoseskilled in the art. Reference may be had, e.g., to U.S. Pat. No.3,601,376 (process for preheating limestone), U.S. Pat. No. 3,617,560(limestone neutralization of dilute acid waste waters), U.S. Pat. No.3,722,867 (method of calcining limestone), U.S. Pat. No. 3,900,434(wallboard tape joint composition comprised of limestone), U.S. Pat. No.4,015,973 (limestone-expanding clay granules), U.S. Pat. No. 4,026,7632(use of ground limestone as a filler in paper), U.S. Pat. No. 4,231,884(water retardant insulation composition comprising treated low densitygranular material and finely divided limestone), U.S. Pat. No. 4,237,025(product comprising lime or limestone and Graham's salt), U.S. Pat. No.4,239,736 (method for increasing the brightness of limestone), U.S. Pat.No. 4,272,498 (process for comminuting and activating limestone byreaction with carbon dioxide), U.S. Pat. No. 4,316,813 (limestone-basedsorbent agglomerates), U.S. Pat. No. 4,390,349 (method for producingfuel gas from limestone), U.S. Pat. No. 4,430,281 (process forpalletizing limestone fines), U.S. Pat. No. 4,594,236 (method ofmanufacturing calcium carbide from limestone), U.S. Pat. No. 4,614,755(protective coating composition comprising a blend of polyvinyl acetate,hydraulic cement, EVA, and limestone), U.S. Pat. No. 4,629,130 (processfor preparing finely divided limestone), U.S. Pat. No. 4,671,208 (clayand limestone composition), U.S. Pat. No. 4,710,226 (fluidization oflimestone slurries), U.S. Pat. No. 4,781,759 (limestone and claytraction aid) U.S. Pat. No. 4,824,653 (method of bleaching limestone),U.S. Pat. No. 5,228,895 (fertilizer and limestone product), U.S. Pat.No. 5,375,779 (process for grinding limestone to a predeterminedparticle size distribution), U.S. Pat. No. 5,908,502 (limestone filledPortland cements), and the like. The entire disclosure of each of theseUnited States patents is hereby incorporated by reference into thisspecification.

Referring to FIG. 1, and in step 12 thereof, limestone is mined. Onemay, e.g., use many of the conventional techniques used for miningminerals. Reference may be had, e.g., to U.S. Pat. No. 3,737,704(control blasting), U.S. Pat. No. 3,775,984 (mining method and method ofland reclamation), U.S. Pat. No. 3,849,927 (mining method using controlblasting), U.S. Pat. No. 4,189,184 (rotary drilling and extractionprocess), U.S. Pat. No. 4,198,097 (method of mining), U.S. Pat. No.4,116,488 (in-situ mining method and apparatus), U.S. Pat. No. 4,134,619(subterranean mining), U.S. Pat. No. 4,323,281 (method for surfacemining), U.S. Pat. No. 4,425,057 (method of mining) U.S. Pat. No.4,699,429 (mining machine system), U.S. Pat. No. 5,667,729 (apparatusand method for continuous mining), U.S. Pat. No. 5,709,433 (apparatusfor continuous mining), U.S. Pat. No. 5,782,539 (wall-to-wall surfacemining process), U.S. Pat. No. 5,810,427 (apparatus and method forcontinuous mining), and the like. The entire disclosure of each of theseUnited States patents is hereby incorporated by reference into thisspecification.

It is preferred that the limestone so mined contain at least about 60weight percent of calcium carbonate. In one preferred embodiment, thelimestone so mined contains at least about 70 (and more preferably atleast about 80) weight percent of calcium carbonate. In anotherembodiment, the limestone contains at least about 85 weight percent ofcalcium carbonate. In another preferred embodiment, the limestone somined contains at least about 90 weight percent of calcium carbonateand, more preferably, at least about 95 weight percent of calciumcarbonate.

In one preferred embodiment, the limestone so mined is biodegradable. Asused in this specification, the term biodegradable refers to a substancethat can be decomposed by the biochemical systems of biologicalorganisms (refer to the means, e.g., by which chickens decomposelimestone fed to them). Reference may be had, e.g., to U.S. Pat. No.3,919,163 (biodegradable containers), U.S. Pat. No. 4,356,572(biodegradable implant used as bone prosthesis), U.S. Pat. No. 5,174,581(biodegradable clay pigeon), U.S. Pat. No. 5,316,313 (frangiblebiodegradable clay target), U.S. Pat. No. 5,651,550 (biodegradableedible target), U.S. Pat. No. 5,993,530 (biodegradable resincomposition), U.S. Pat. No. 6,029,395 (biodegradable mulch mat), U.S.Pat. No. 6,573,340 (biodegradable polymer films), U.S. Pat. No.6,890,872 (fibers comprising starch and biodegradable polymers), and thelike. The entire disclosure of each of these United States patents ishereby incorporated by reference into this specification.

In one preferred embodiment, the limestone so mined contains less than10 milligrams per kilogram of arsenic, less than 150 milligrams perkilogram of barium, less than 2 milligram per kilogram of cadmium, lessthan 10 milligrams per kilogram of chromium, less than 10 milligrams perkilogram of lead, less than 0.4 milligrams per kilogram of mercury, lessthan 2.0 milligram per kilogram of selenium, and less than 0.4milligrams per kilogram of mercury. As will be apparent, 1 milligram perkilogram is equivalent to 1 part per million.

In one preferred embodiment, the limestone so mined contains less thanabout 100 parts per million of a leachable metal selected from the groupconsisting arsenic, barium, cadmium, chromium, lead, mercury, selenium,silver, and mixtures thereof. The presence, or absence, of such aleachable metal may be determined, e.g., in accordance with the“Toxicity Characteristic Leaching Procedure” (“TCLP”) that is set forthin the Environmental Protection Agency (EPA) method SW 846-1311. This“TCLP” test is well known to those skilled in the art and is describedin, e.g., U.S. Pat. No. 5,127,963 (process for detoxifying leadcontaminated materials), U.S. Pat. No. 5,193,936 (fixation andstabilization of lead in contaminated soil and solid waste), U.S. Pat.No. 5,196,620 (fixation and utilization of ash residue from theincineration of municipal solid waste), U.S. Pat. No. 5,245,114(immobilization of lead in bottom ash), U.S. Pat. No. 5,252,003(attenuation of arsenic leaching from particulate material), U.S. Pat.No. 5,278,982 (fixation and stabilization of metals in contaminatedmaterials), U.S. Pat. No. 5,397,478 (fixation and stabilization ofchromium in contaminated materials), U.S. Pat. No. 5,421,906 (methodsfor removal of contaminants from surfaces), U.S. Pat. No. 5,430,223(immobilization of lead in solid residues from reclaiming metals), U.S.Pat. No. 5,430,234 (process for removing phosphorous and heavy metalsfrom phosphorous trichloride still bottoms residue), U.S. Pat. No.5,678,235 (safe ceramic encapsulation of hazardous waste with specificshale material), U.S. Pat. No. 5,859,306 (method of treatingarsenic-contaminated matter using aluminum compounds), U.S. Pat. No.5,806,908 (water insoluble heavy metal stabilization process), U.S. Pat.No. 5,877,393 (treatment process for contaminated waste), U.S. Pat. No.5,897,685 (recycling of CdTe photovoltaic waste), U.S. Pat. No.5,898,093 (treatment process for contaminated waste), U.S. Pat. No.6,717,363 (control of leachable mercury in fluorescent lamps bygelatin), U.S. Pat. No. 6,383,398 (composition and process forremediation of waste streams), U.S. Pat. No. 6,590,133 (reducing leadbioavailability), U.S. Pat. No. 6,637,354 (coal combustion productsrecovery process), U.S. Pat. No. 6,688,811 (stabilization method forlead projectile impact area), U.S. Pat. No. 6,781,302 (low pressuremercy vapor fluorescent lamps), and the like. The entire disclosure ofeach of these United States patents is hereby incorporated by referenceinto this specification.

By way of illustration, the TCLP test is discussed in U.S. Pat. No.5,860,908, the entire disclosure of which is hereby incorporated byreference into this specification. This patent discloses that “Theleaching of heavy metal bearing wastes and human and biological exposureto heavy metal content has long been of concern to environmentalregulators and waste producers. Under the Resource Conservation andRecovery Act (RCRA), solid waste is classified by the U.S. EnvironmentalProtection Agency (EPA) as hazardous waste if excessive amounts of heavymetals leach from the waste when tested under the ToxicityCharacteristic Leaching Procedure (TCLP). EPA also regulates the landdisposal of certain heavy metal bearing wastes depending on the contentof the heavy metals regardless of the leaching potential. In addition,several state governments require solid wastes with elevated levels ofheavy metals be disposed of as a hazardous waste. Disposal of waste at ahazardous waste landfill is typically more expensive than disposal atnon-hazardous waste landfills.”

Referring again to FIG. 1, it should be noted that not only does thelimestone so mined contains less than 100 parts per million of aleachable metal selected from the group consisting arsenic, barium,cadmium, chromium, lead, mercury, selenium, silver, and mixturesthereof, but it also preferably contains less than 100 parts per millionof a metal selected from the group consisting arsenic, barium, cadmium,chromium, lead, mercury, selenium, silver, and mixtures thereof,regardless of whether such metal is “leachable” in accordance with theTCLP test.

There has been some concern expressed that roofing granules made fromslag might contain carbon-containing residues that might be mutagenicand/or carcinogenic when incorporated into living biological organisms.Thus, e.g., the “oxidation products” from cigarette smoke have beenreported to contain many different mutagen and/or carcinogens.Similarly, the “oxidation products” produced by cooking a steak over avery high flame also contain many mutagens and/or carcinogens.

It appears that many roofing granules are prepared by combusting coal.Thus, e.g., U.S. Pat. No. 6,258,456, the entire disclosure of which ishereby incorporated by reference into this specification, discusses thepreparation of roofing granules from slag produced from the combustionof coal, disclosing that, “Each year many tons of materials such as slagand fly ash resulting from combustion of coal in boilers, hereinafterreferred to as coal slag and coal fly ash, found in electric generatingplants are produced. In the United States in 1993, for example, over 5.6million metric tons of coal slag and 43.7 million metric tons of coalfly ash were produced as coal combustion byproducts. The greatest use ofsuch materials is found in roofing granules and as sandblastingmaterials. Other uses are found in cement and concrete products, snowand ice control, and grouting materials. However, only about 55% of thecoal slag and only about 22% of the coal fly ash is incorporated intouseful products. The remaining amount is generally disposed of inlandfills.”

Referring again to FIG. 1, and in one preferred embodiment, both thelimestone mined (see FIG. 1) and the coated granular material madetherefrom (see FIG. 1) preferably contain less than 100 parts permillion of a metal selected from the group consisting arsenic, barium,cadmium, chromium, lead, mercury, selenium, silver, and mixturesthereof.

In one preferred embodiment, the mined limestone used in the roofinggranules of this invention has a hardgrove grindability index (HGI) ofless than about 70 and, more preferably, less than about 68. In anotherpreferred embodiment, the hardgrove grindabilty index of the limestoneis less than 60 and, more preferably, from about 55 to about 58.

The hardgrove grindability index is well known to those skilled in theart and is described, e.g., in the specification and the claims of U.S.Pat. No. 4,419,456 (method for the disposal of shot coke), U.S. Pat. No.4,521,278 (method for producing needle coke), U.S. Pat. Nos. 5,007,987,5,389,353, 5,882,377, 6,882,517, and the like. The entire disclosure ofeach of these United States patents is hereby incorporated by referenceinto this specification.

The test for determining the hardgrove grindability index is describedin A.S.T.M. Standard Test D409-85 “Standard Test Method for Grindabilityof Coal by the Hardgrove-Machine Method.” This A.S.T.M. test is alsodescribed, e.g., in U.S. Pat. No. 4,420,445 (coal pellets production),U.S. Pat. Nos. 4,419,456, 6,083,289, 6,692,544, and the like. The entiredisclosure of each of these United States patents is hereby incorporatedby reference into this specification.

In one embodiment, the limestone used contains less than about 4 weightpercent of magnesium and, more preferably, less than about 2 weightpercent of magnesium.

In one preferred embodiment, the limestone mined contains less than 2weight percent of acid insoluble products, such as silica, aluminumoxides, iron oxides. In one aspect of this embodiment, the limestonemined contains less than 1.5 weight percent of acid insolubleproduct(s). It is preferred that the limestone contain less than about 1weight percent of silica and less than 0.5 weight percent of aluminumoxide material and/or iron oxide material.

In one embodiment, the ore used in the process of this invention isdolomite, and it may replace some or all of the limestone used in theprocess.

Dolomite is a carbonate of calcium and magnesium that may be representedby the formula CaMg(CO₃)₂. This carbonate mineral has a hexagonalsymmetry and a structure similar to that of calcite, but with alternatelayers of calcium ions being completely replaced by magnesium. See,e.g., page 568 of Sybil P. Parker's “McGraw-Hill Dictionary ofScientific and Technical Terms,” Fourth Edition (McGraw-Hill BookCompany, New York, N.Y., 1989).

In one preferred embodiment, dolomitic limestone is used in the process10.

Referring again to FIG. 1 and in step 14 thereof, the limestone fromstep 12 that preferably has the required degree of hardgrovegrindability is subjected to crushing in step 14.

In one preferred embodiment, and referring again to FIG. 1, a series offour or more crushers, such as rotary impact crushers, are used to crushthe limestone to ⅛″, i.e. substantially all of the crushed particles aresmaller than ⅛″. These crushers are well known and are described, e.g.,in U.S. Pat. No. 3,608,841 (rotary impact crusher), U.S. Pat. No.3,737,678 (rotary impact crusher having a continuous rotarycircumference), U.S. Pat. No. 4,844,364 (rotary impact crusher), U.S.Pat. No. 4,844,365 (rotary impact crusher), U.S. Pat. No. 4,877,192(rotary impact crusher main wear tip), U.S. Pat. No. 4,923,131 (rotaryimpact crusher rotor), and the like. The entire disclosure of each ofthese United States patents is hereby incorporated by reference intothis specification.

In this embodiment, and in the first crushing step, the size of thelimestone is preferably reduced to minus 6 inches, that is, the topmaximum size is less than about 6 inches. The first crushed material maythen be crushed in a second crusher to reduce its size to about minus1.5″. The second crushed material may then be crushed in a third crusherto reduce its size to about minus 0.375″. The third crushed material maythen be crushed in a fourth crusher to reduce its size to about minus ⅛″

In another embodiment, the material from the first crusher is preferablyfeed to a screener, which separates the material so fed into varioussize fractions. One may use any of the screeners known to those skilledin the art. Thus, one must use a vibratory screener such as, e.g., ascreener utilizing mechanical vibration with inclined screen surfaces, ascreener using mechanical vibration with horizontal screen surfaces, anelectromagnetic vibratory screener, and the like.

By way of further illustration, one may use one or more of the screeningdevices disclosed at pages 21-39 to 21-45 of Robert H. Perry et al.'s“Chemical Engineer's Handbook,” Fifth Edition (McGraw-Hill Book Company,New York, N.Y., 1973. Thus, e.g., one may use Grizzly screens (see pages21-40 to 21-41), revolving screens (see page 21-41), mechanical shakingscreens (see page 21-41), vibrating screens (see page 21-41),mechanically vibrated screens (see page 21-41), electrically vibratedscreens (see page 21-41), oscillating screens (see page 21-42),reciprocating screens (see page 21-42), gyratory screens (see page21-42), gyratory riddles (see page 21-42), and the like.

In this embodiment, any material from the screener with particles sizedgreater than about 1.75 inches is preferably fed via line a secondcrusher, wherein it is crushed to sizes smaller than 1.75 inches.Material from the second crusher is then fed to a third crusher thatreduces the size of the limestone particles to a top size of 0.625inches.

Many other means of producing crushed minus ⅛″ ore may be used in theprocess 10. Thus, e.g., one may use a series of many impact crushingassemblies which, by means of a multiplicity of crushers and/orclassifiers, produce many differently sized products.

Referring again to FIG. 1, the ⅛″ crushed ore from step 14 is then fedto drying step 16 in which it is dried to a moisture content of lessthan about 1 weight percent and, preferably, to less than about 0.1weight percent. It is preferred to use a rotary dryer to effectuate suchdrying. These dryers are described, e.g., on pages 20-32 to 20-44 Perryand Chilton's “Chemical Engineers' Handbook,” Fifth Edition (McGraw-HillBook Company, New York, N.Y., 1973). It is preferred to use atemperature of at least about 220 degrees Fahrenheit in the rotary dryerin order to vaporize all of the water in the ore so that it is “bonedry” (i.e., it contains less than about 0.1 weight percent of water).

The dried material from step 16 is then screened in step 18. In ispreferred to utilize a multiplicity of multiple deck screeners, such as,e.g., four multiple deck screeners, in such step 18.

Multiple deck screeners are well known to those skilled in the art;reference may be had to U.S. Pat. No. 5,341,939, the entire disclosureof which is hereby incorporated by reference into this specification.This patent claims (in claim 1 thereof) “1. A vibrating screen apparatusfor material screening including in combination: a frame; at least firstand second elongated vibrating screen decks having first and secondsides and first and second ends; first and second pivot means forpivotally mounting the first ends of said first and second vibratingscreen decks, respectively, on said frame, with said first vibratingscreen deck located above said second vibrating screen deck; first andsecond means coupled with first and second said vibrating screen decks,respectively, for rotating said first and second vibrating screen decksabout said first and second pivot means for varying the angle of saidfirst and second vibrating screen decks relative to said frame; meansfor vibrating said first and second vibrating screen decks; and flexiblecurtain members extending between the first sides and the second sides,respectively, of said first and second vibrating screen decks to ensurethat material falling through said first vibrating screen deck dropsonto said second vibrating screen deck.”

U.S. Pat. No. 5,341,939, in column 1 thereof, discusses other multipledeck screeners. It is disclosed in such column 1 that, “Vibratingmaterial sorting screens are used in a variety of applications,including sand and gravel businesses and in mining operations. Suchvibrating screens are used to sort material size, and typically comprisean elongated deck, which slopes downwardly from the feed end to thematerial delivery end. Usually, the decks are mounted in a deck holdingframe, which, in turn, is supported on springs extending to a platformon a support surface. An eccentric vibrator is employed to vibrate theframe on the springs to cause a shaking of the material poured onto thevibrating screen deck to facilitate the movement of the material downthe deck, and to expedite the material separation. Both the aperture ofthe screen and the size of the deck determines the separation size ofthe materials, and any material which is larger than the screen aperturefinally is supplied from the end of the deck to a suitable receptacle.All material which is smaller than the screen aperture falls through thedeck for further separation or processing.”

U.S. Pat. No. 5,431,939 also discloses (in such column 1) that: “In somemining applications, the vibrating screen apparatus has two deckslocated one above the other, with the larger screen aperture on the topdeck and a smaller screen aperture on the lower deck. In the sand andgravel business, three to five decks frequently are used, with the decksprogressing in screen aperture from the largest at the top to thesmallest at the bottom. Usually, all of these decks are mounted togetherin a single frame, vibrated by a single vibrating apparatus. The slopeof each deck, from the feed end or material receiving end to thedelivery end, is fixed once the vibrating screen apparatus is assembled.In addition, a single vibrating weight and drive motor is used; so thatthe magnitude and frequency of vibration of the entire unit is thesame.”

U.S. Pat. No. 5,431,939 also discloses (in such column 1) that, “When amultiple deck vibrating screen unit is employed, the magnitude andfrequency of the vibration necessarily is a compromise between theoptimum magnitude and speed of vibration required for the deckseparating the larger size materials and the magnitude and speed ofvibration required for the deck which is separating the smaller sizedmaterials. In addition, the rate at which materials traverse the deckfrom the feed end to the delivery end varies, depending upon the size ofthe material; so that a compromise generally is made in the slope of thedecks during the manufacturing of a multiple deck unit. In some cases,the slope angle of the different decks can be made to vary relative toone another; but once the unit is made, the different slope anglescannot further be adjusted in a typical deck.”

U.S. Pat. No. 5,341,939 also discloses that, “When multiple deck unitshaving three or more decks are employed, the compromises, which must bereached between the slope or angle of the different decks and themagnitude and speed of the vibrator, result in ever greater departuresfrom the optimum, which would be desired for each deck having a singlescreen size. In view of this, it is desirable to provide a vibratingscreen apparatus for a multiple deck unit which may be operated witheach deck vibrated independently of the others, and where the angle orslopes of the decks may be independently varied, as desired.”

One preferred multideck screener is the “Multi-Vib Screener” sold byMidwestern Industries, Inc. of Masillon, Ohio. This screener isdescribed on the website for Midwestern Industries as follows: “Untilrecently, vibrating screens were calculated by using only twodimensions−width determined capacity and length determined efficiency.Midwestern Industries' Multi-Vib screens utilize a thirddimension—‘depth’—in addition to width and length to calculate size.”

It is also disclosed on such website that, “The ‘depth’ dimension isaccomplished by using five screening decks arranged one above the otherto impart rapid vertical movement to the material being screened. Thematerial passes through the top coarse screen to the progressivelysmaller screen openings below where it is retained—or passes through thefinest screen on the fifth deck . . . . Multi-Vib units are available inthree models . . . . They are powered by belt-free vibrating motors . .. ”

In the embodiment depicted in FIG. 1, a series of at least four multipledeck screeners (not shown) each will have an 8 mesh screen (2.38millimeter sieve openings), a 10 mesh screen (1.68 millimeter openings),an 18 mesh screen, a 32 mesh screen (500 micron openings), and a 40 meshscreen. These screeners thus produce, e.g., a 10×18 feed (i.e., a feedthat passes through the 10 mesh screen but is retained on the 18 meshscreen), an 18×32 feed (i.e., a feed that passes through the 18 meshscreen but is retained on the 32 mesh screen), a 32×40 feed, etc.

The 8×10 output from the multiple deck screeners can either be utilizedas a non-headlap product and/or recycled in whole or in part. When it isto be recycled, it may be crushed again in one of the crushers (such as,e.g., the fourth crusher) and then fed again to one or more of themultiple deck screeners.

The other outputs from the different multiple deck screeners may be fedto bin 20 (“bin 1”), bin 22 (“bin 2”), bin 24 (“bin 3”), and/or bin 24(“bin 4”), and the output from one or more of these bins may then becombined in step 28 and/or subject to “superfine air classification” instep 30 in order to produce the desired particle size distribution.

In the embodiment depicted in FIG. 1, different feeds from the multideckscreeners and/or different combinations of feeds and/or differentamounts of the feeds are fed to each of the bins 1, 2, 3, and 4 so that,when the material in these bins is combined and/or further purified (inturbine classification step 30), the desired particle size distributionwill be obtained. As will be apparent, there are a substantial number ofcombinations of conditions that will produce the desired particle sizedistribution. For any particular feed stock (such as, e.g., the 18/32feedstock), one may feed some, all, or none of such feed stock to bin 1and/or bin 2 and/or bin 3 and/or bin 4. One may, e.g., feed materialfrom bin 1 and/or bin 2 and/or bin 3 and/or bin 4 to the turbineclassification step 30 prior to the time such material is combined instep 28.

In one embodiment, not shown, a controller (not shown) is operativelyconnected to laboratory 32 and, additionally, bin 20, bin 22, bin 24,bin 26, mixer 38, and classifier 30. By analyzing and monitoring thematerial present in each of these locations, the controller can modifythe feeds from the multideck screeners and/or from the bins 20, 22, 24,and 26 and/or from the turbine classifier 30 to insure that the materialdischarged via line 34 from the turbine classifier has the desiredparticle size distribution.

Referring again to FIG. 1, in one embodiment, each of the multideckscreeners (not shown) comprises a 4 mesh screen, an 11 mesh screen, and18 mesh screen, a 24 mesh screen, and a 32 mesh screen.

In one embodiment, the material retained on the 18 mesh screen may becoated with pigment and/or adhesion promoting agent (as is describedelsewhere in this specification) and used to prepare headlap particles.

In one embodiment, some or all of the material retained on the 32 meshscreen may be “classified” in the superfine turbine classification step30 described elsewhere in this specification to produce a coarsefraction that may be used in headlap production and a fine fraction thatmay either be discarded or used to produce other products.

Referring again to FIG. 1, some or all of the material fed to bins 20,22, 24, and 26, either before or after they are combined in step 28, maybe fed to a superfine turbine classifier in step 30. In such step 30,the feed(s) are subjected to air flow classification in order to reducethe concentration of fines” in such feed(s). Thus, e.g., theconcentration of particles smaller than 250 microns may be reduced insuch step 30.

Airflow separators are well known to those skilled in the art, and theyare referred to in the claims of U.S. Pat. No. 5,541,831 (computercontrolled separator device), U.S. Pat. No. 5,943,231 (computercontrolled separator device), U.S. Pat. No. 6,351,676 (computercontrolled separator device), and the like. The entire disclosure ofeach of these United States patents is hereby incorporated by referenceinto this specification.

Air flow separators are also discussed in U.S. Pat. No. 3,772,857 (waterair separator), U.S. Pat. No. 3,874,444 (duo-baffle air separatorapparatus), U.S. Pat. No. 3,877,454 (air separator), U.S. Pat. No.3,962,072 (air separator apparatus), U.S. Pat. No. 4,662,915 (powder airseparator), U.S. Pat. No. 4,824,559 (rotary air separator), U.S. Pat.No. 5,244,481 (vertical air separator), U.S. Pat. No. 5,788,727(centrifugal air separator), U.S. Pat. No. 6,053,967 (air separator),U.S. Pat. No. 6,664,479 (method and air separator for classifyingcharging material reduced in size), and the like.

In one preferred embodiment, the air flow separator is a 72 inch“SuperFine Air Classifier” manufactured by Sturtevant, Inc. of 348Circuit Street, Hanover, Ma.

Referring again to FIG. 1, and to the preferred embodiment depictedtherein, the material fed from the air flow separation step 30 via line34 preferably ranges in particle size from about 100 to about 2,500microns, with at least 60 weight percent of the particles having sizesin the range of from about 600 to about 1400 microns. In one embodiment,at least about 70 weight percent of the particles have sizes in therange of from about 600 to about 1400 microns. In another embodiment, atleast about 80 weight percent of the particles have sizes in the rangefrom about 600 to about 1400 microns. In yet another embodiment, atleast about 85 weight percent of the particles have sizes in the rangeof from about 600 to about 1400 microns.

In one embodiment, the material fed from airflow separator 34 (via line38) ranges in particle size from about 500 to about 2500 microns (and,more preferably, from about 500 to about 2,000 microns). The airflowseparator 30 preferably reduces the “fines content” of the particlecompact so that the output in line 34 contains less than about 4 weightpercent of particles smaller than 250 microns (60 mesh) and, morepreferably, less than about 3 weight percent of particles smaller than250 microns. In one embodiment, the material fed via line 34 containsless than 2 weight percent of material smaller than 250 microns and,more preferably, less than about 1 weight percent of material smallerthan about 250 microns. In one embodiment, the material fed via line 34contains less than about 0.4 weight percent of material smaller than 250microns.

Without wishing to be bound by any particular theory, applicants believethat conventional air flow separators cannot readily be used to producea limestone headlap product with suitable properties. However, theSturtevant machine described elsewhere in this specification works well.

In one embodiment, the material fed from airflow separator 30 containsat least 95 weight percent of particles smaller than 3,350 microns.

In one embodiment, the material fed from air flow separator 30 containsat least 95 weight percent of particles smaller than 2,360 microns.

In one embodiment, the material fed from airflow separator 30 containsat least 95 weight percent of particles smaller than 1,700 microns.

In one embodiment, the material fed from airflow separator 30 containsat least 60 weight percent of particles smaller than 1,000 microns.

In one embodiment, the material fed from airflow separator 30 containsat least 30 weight percent of particles smaller than 850 microns.

In one embodiment, the material fed from airflow separator 30 containsat least 3 weight percent of particles smaller than 600 microns.

In one embodiment, the material fed from airflow separator 30 containsat least 97 weight percent of particles greater than 425 microns.

In one embodiment, the material fed from airflow separator 30 containsat least 98 weight percent of particles greater than 300 microns.

In one embodiment, the material fed from airflow separator 30 containsat least 98 weight percent of particles greater than 250 microns.

In one embodiment, the material fed from airflow separator 30 containsat least 99 weight percent of particles greater than 212 microns.

In one embodiment, the material fed from airflow separator 30 containsat least 99.5 weight percent of particles greater than 180 microns.

In one embodiment, the material fed from airflow separator 30 (via line34) contains at least 97 weight percent of material greater than 30 mesh(with an average of 97.4 weight percent material greater than 30 mesh),at least 99 weight percent of material greater than 40 mesh (with anaverage of 99.07 weight percent greater than 40 mesh), at least 99weight percent of material greater than 60 mesh (with an average of99.55 weight percent greater than 60 mesh), and at least 99 weightpercent of material greater than 100 mesh (with an average of 99.73weight percent greater than 100 mesh). In one aspect of this embodiment,the material fed via line 34 contains from about 2 to about 6.5 weightpercent of material greater than 12 mesh (with an average of 4.15 weightpercent greater than 12 mesh), from about 35 to about 63 weight percentof material greater than 16 mesh (with an average of 45.77 weightpercent greater than 16 mesh), and from 69 to 94 weight percent greaterthan 20 mesh (with an average of 78.95 weight percent greater than 20mesh).

In the process depicted in FIG. 1, at least four gradations of limestoneparticles are combined to make the limestone headlap material.

In another embodiment, the material fed from classifier 30, via line 24,contains from about 98.0 to 99.9 weight percent of particles smallerthan 10 mesh (1700 microns), from about 93.5 to about 97.5 weightpercent of particles smaller than 12 mesh (1400 microns), from about 38to about 60 weight percent of particles smaller than 1000 microns, fromabout 5 to about 20 weight percent of particles smaller than 850microns, from about 0.5 to about 6 weight percent of particles smallerthan 600 microns, from about 0.1 to about 1.8 weight percent ofparticles smaller than 425 microns (40 mesh), and from about 0.04 toabout 1.2 weight percent of particles smaller than 250 microns.

Referring again to FIG. 1, and to the preferred embodiment depictedtherein, a portion of the material produced in airflow separator may beperiodically withdrawn via line 33 to laboratory 32, in order to testthe particle size distribution of such material; similarly, material maybe withdrawn from mixer 28 to lab 32. The particle size analysis may beconducted by conventional means. Reference may be had, e.g., to pages92-109 of Barry A. Wills “Mineral Processing Technology,” Sixth Edition(Butterworth Heinemann, Oxford, 1997. Reference also may be had, e.g.,to U.S. Pat. No. 4,288,162 (measuring particle size distribution), U.S.Pat. No. 4,736,311 (particle size distribution measuring apparatus),U.S. Pat. No. 4,742,718 (apparatus for measuring particle-sizedistribution), U.S. Pat. No. 5,094,532 (method and apparatus formeasuring small particle size distribution), U.S. Pat. No. 5,164,787(apparatus for measuring particle size distribution), U.S. Pat. No.5,185,641 (apparatus for simultaneously measuring large and smallparticle size distribution), U.S. Pat. No. 5,578,771 (method formeasuring particle size distribution), U.S. Pat. No. 5,682,235 (dryparticle-size distribution measuring apparatus), U.S. Pat. No. 6,191,853(apparatus for measuring particle size distribution and method foranalyzing particle size distribution), U.S. Pat. No. 6,252,658 (particlesize distribution measuring apparatus), U.S. Pat. No. 6,281,972 (methodand apparatus for measuring particle size distribution), U.S. Pat. No.6,864,979 (particle size distribution measuring apparatus), and thelike. The entire disclosure of each of these United States patents ishereby incorporated by reference into this specification.

Referring again to FIG. 1, two mixers (mixer 36 and mixer 38) are shownin the preferred process depicted. Mixer 36 is preferably used to addpigmented coating material to the mineral composition, and is preferablyused on darkened headlap material. In any event, it is preferred to feedall of the mineral composition material first to mixer 38 and add (inone embodiment) adhesion promoter material in mixer 38.

Referring again to FIG. 1, the material fed via lines 34 to mixers 38and 36 preferably has the desired particle size distribution and adistribution modulus of from about 0.08 to about 0.14. If either or bothof these values are not as desired, they may be adjusted by adding tomixer 36 (via line 35) more particulate material After such addition,and appropriate mixing, sampling of the material in mixer 36 may occurin laboratory 32, and the process may be repeated until the desiredvalues have been obtained.

Once the desired particle size distribution in mixer 36 has beenobtained, and after such particles have preferably been pretreated witha pigmented material, one may pass such particles to mixer 38 in whichone may add a mixture of oil and antistrip agent via line 39 to coat theinorganic particles in such mixer. Alternatively, one may add either theoil alone, or the antistrip agent alone, or neither the oil nor theantistrip agent. The goal, in one embodiment, is to produce a coating onsuch particulate matter with a thickness of from about 200 to about 2000nanometers and, preferably from about 300 to about 1200 nanometers.

Preferred Adhesion Improving Additives

By way of yet further illustration, in process 10 one may use theadhesion improving additives (“antistrip agents”) disclosed in U.S. Pat.No. 4,038,102, the entire disclosure of which is hereby incorporated byreference into this specification. Claim 1 of this patent describes, “1.An additive for improving the adhesion of asphalt to aggregatecomprising an ether amine having the general formula: [Figure] wherein:R1 is a hydrocarbon group having from about six to about sixteen carbonatoms, selected from the group consisting of alkyl and alkenyl; R2, r3,r4 and R5 are selected from the group consisting of hydrogen and alkylradicals having from one to about two carbon atoms; n1 and n2 arenumbers within the range from one to about four; x1 and x2 are numberswithin the range from zero to about five, the sum of x1 and x2 beingfrom one to five; the total number of carbon atoms in each . . . unitbeing from one to about four; and an alkanolamine having the formula: .. . wherein: R6 and R7 are selected from the group consisting ofhydrogen and alkyl groups having from one to about two carbon atoms; n3is a number within the range from two to about four; x3 is a numberwithin the range from one to about three; the total number of carbonatoms in each . . . unit being with the range from two to four.” Some ofthe “ether amines” described by such formula include, e.g., “ . . .octoxyethylamine, decoxyethylamine, dodecoxyethylamine,tetradecoxyethylamine, hexoxypropylamine, octoxypropylamine,nonoxypropylamine, decoxypropylamine, dodecoxypropylamine,tetradecoxypropylamine, palmityloxypropylamine, myristyloxypropylamine,hexyl dioxyethylene oxyethylamine, octyl trioxyethylene oxyethylamine,dodecyl tetraoxyethylene oxyethylamine, myristyl dioxyethyleneoxypropylamine, octyl tetraoxyethylene oxypropylamine, dodecyltetraoxyethylene oxypropylamine, octyl dioxypropylene oxypropylamine,decyl trioxypropylene oxyethylamine, tetradecyl tetraoxypropyleneoxypropylamine, octyl oxypropylene oxypropylamine, palmityltetraoxypropylene oxypropylamine, heptenyl oxypropylene oxypropylamine,decenyl dioxyethylene oxyethylamine, octenyl oxypropylene oxyethylamine,dodecenyl tetraoxypropylene oxypropylamine, octyloxybutyleneoxbutylamine, decyl trioxybutylene oxybutylamine, dodecyltetraoxybutylene oxyethylamine, palmityl dioxybutylene oxypropylamine,decyl tetraoxy propylene oxypropylamine, and dodecyloxy propyleneoxyethylamine.”

By way of further illustration, one may use the amine antistrippingagent disclosed in U.S. Pat. No. 4,721,159, the entire disclosure ofwhich is hereby incorporated by reference into this specification. Claim1 of this patent describes, “1. An asphaltic composition comprising anasphalt admixed with an aggregate and at the interface between saidasphalt and said aggregate the reaction product of an amine antistripand an acid salt in an amount sufficient to bind said asphalt to saidaggregate; said acidic salt being a divalent or trivalent metal salt ofan inorganic acid.” In the background section of this patent, it isdisclosed that, “Various efforts to improve adhesion are detailed inpatents such as U.S. Pat. No. 2,582,823 and U.S. Pat. No. 2,582,824 toFowkes in which the amine type of antistripping agents or the use ofacids and soaps, as well as the use of lime, are discussed and theirdisadvantages noted. In an attempt to improve these well-known problems,with respect to cut-back asphaltic compositions, there is disclosed apriming solution to be used to attain this better adhesion. For thispurpose, Fowkes discloses using alkaline metal salts of certaininorganic acids to form a wet aggregate which is admixed with thecut-back asphalt. Such priming solution does not give the necessaryadhesion, does not work with all types of aggregates and does not worksatisfactorily with hot-mix asphaltic compositions. Under the press ofheavy traffic the resultant compositions crack and lose whatever allegedantistripping function they possess. U.S. Pat. No. 2,469,728 describesanother effort to improve the adhesion of the asphalt to the mineralaggregate consisting of mollusk shells in which the shells are firsttreated with a dilute solution of a strong mineral acid and the thustreated aggregate then coated with asphalt. Here again, such is limitedto a cut-back asphalt as set forth in column 1.”

By way of yet further illustration, one may use one or more of thecompositions claimed in U.S. Pat. No. 5,064,571, the entire disclosureof which is hereby incorporated by reference into this specification.This patent claims (in claim 1 thereof), “Mixtures of amido-aminesprepared by a process comprising reacting at least one first componentcomprising at least one compound selected from the group consisting ofmono- and dicarboxylic acids and acid esters, with a second componentcomprising polyoxyalkyleneamine bottoms products, where the reaction isconducted in the temperature range from about 25° to about 280° C. andat a pressure in the range from about atmospheric to about 200 psig.”

By way of further illustration, one may use one or more of thehydroxylamines described in U.S. Pat. No. 6,290,772, the entiredisclosure of which is hereby incorporated by reference into thisspecification. This patent claims (in claim 1 thereof), “1. A hydrauliccement composition comprising a mixture of Portland cement and, in anamount of up to 0.1 percent by weight of said cement, an hydroxylamineselected from the group consisting ofN,N-bis(2-hydroxyethyl)-2-propanolamine andN,N-bis(2-hydroxypropyl)-N-(hydroxyethyl)amine, said amount beingeffective to enhance the compressive strength of the cement compositionafter 1, 3, and 7 days.” In the “background” portion of this patent,some other amines which also may be used are described. It is disclosedthat, “Various other additives may be added to cement to alter thephysical properties of the final cement. For example, alkanolamines suchas monoethanolamine, diethanolamine, triethanolamine and the like areknown to shorten the set time (set accelerators) as well as enhance theone-day compressive strength (early strength) of cements. However, theseadditives have little beneficial effect on the 28-day set strength ofthe finished cement and in some cases may actually diminish it. Thisbehavior is described by V. Dodson, in “Concrete Admixtures,” VanReinhold, N.Y., 1990, who states that calcium chloride, the best knownset-time accelerator and early-age strength enhancer reduces compressivestrengths at later-ages.”

U.S. Pat. No. 6,290,772 also discloses that “U.S. Pat. Nos. 4,990,190,5,017,234 and 5,084,103, the disclosures of which are herebyincorporated by reference, describe the finding that certain highertrihydroxyalkylamines such as triisopropanolamine (hereinafter referredto as “TIPA”) and N,N-bis(2-hydroxyethyl)-2-hydroxypropylamine(hereinafter referred to as “DEIPA”) will improve the late strength(strength after 7 and 28 days of preparation of the wet cement mix) ofPortland cement, especially Portland cements containing at least 4percent C4 AF. The strength-enhancing higher trihydroxyalkylamineadditives described in these patents are said to be particularly usefulin blended cements.”

By way of yet further illustration, one may use one or more of the“organic modifiers” disclosed in U.S. Pat. No. 6,503,740, the entiredisclosure of which is hereby incorporated by reference into thisspecification. Claim 1 of this patent describes, “1. A self-cleaningtreatment media capable of acting upon at least one chemical contaminantin an aqueous composition assisting in the decomposition of thatcontaminant to at least one suitable lower molecular weight compound,the treatment media comprising: a mineral-based substrate present ingranular form, the mineral-based substrate being a charged materialselected from the group consisting of clays, clay analogs, syntheticresins and mixtures thereof; a compound capable of providing organicsurface modification to a portion of the mineral-based substrate, theorganic modification compound comprising quaternary amines, wherein thequaternary amines are selected from the group consisting of ditallowdimethyl ammonium chloride, hexadecyl ammonium chloride, octadecylammonium chloride, di-methyl di-hydrogenated tallow ammonium chloride,dicocodimethyl ammonium chloride, and mixtures thereof, and wherein themineral-based substrate contains the organic modification compound; andat least one strain of microbial material engrafted on the surface ofthe mineral-based substrate containing the organic surface modificationcompound, the microbial material capable of facilitating decompositionof the at least one chemical contaminant in the aqueous composition;wherein the strain of microbial material has a biological activity, andwherein the organic surface modification compound is one which permitssufficient biological activity of the microbial material when themicrobial material and the organic surface modification compound areboth present on the mineral-based substrate.”

U.S. Pat. No. 6,503,740 also discloses how to modify the mineral-basedsubstrate, stating that, “The manner in which organic modificationoccurs can be by any method known to those skilled in the art.Heretofore, it was believed that quaternary amines used to modify thesurfaces of the substrates such as those discussed previously werebiocidal and would de-activate bacterial material which came intocontact with the amine material. The present invention is predicated onthe unexpected discovery that specific classes of quaternary amines arenon-biocidal to target bacteria. Indeed, it has been found that thequaternary amines employed in the present invention provide actualenhancement to the bacterial colonies inoculated on the surface of theclay or mineral material. Without being bound to any theory, it isbelieved that this is due to the ability of the quaternary aminematerial to provide alcoholic materials such as isopropyl alcohol innutrient level concentration when the quaternary amine is employed toorganically modify the substrate materials; particularly those specifiedin the foregoing discussion.”

U.S. Pat. No. 6,503,740 also discloses that, “The quaternary amineemployed in the process of the present invention is one which will bebiologically supportive of inoculated bacteria, i.e., not adverselyaffect bacterial activity when the quaternary amine is employed toprovide organically modified clays and mineral materials. The preferredquaternary amine can be generally characterized as an ammonium compoundhaving 12 to 18 carbon atoms. The quaternary amines employed in thepresent invention are preferably selected from the group consisting oforganically modified hydrogenated tallow ammonium chlorides, ditallowdimethyl ammonium chloride, hexadecyl and octadecyl ammonium chlorideand derivatives thereof. Most preferably, the quaternary amine isselected from the group consisting of di-methyl di-hydrogenated tallowammonium chloride, dicocodimethyl ammonium chloride, and mixturesthereof.”

U.S. Pat. No. 6,503,740 also discloses that, “In the preferredembodiment, the quaternary amine of choice is employed at a ratiosufficient to provide organic modification without adversely affectingbiological activity of the target microbes or their ability to graft onthe available surface of the mineral material. The preferred range ofquaternary amine to clay or mineral material is between about 10% to100% amine to clay or mineral respectively, with a range between about10% to 45% and about 10 g to 100 g being preferred; and ranges betweenabout 36 g to 100 g, and 48 g to 100 g being most preferred. In apreferred embodiment, the mineral-based substrate and the organicsurface modification compound are present in a ratio between about 10parts to about 100 parts; and about 5 parts to about 150 parts, surfacemodification compound to mineral-based substrate respectively.”

U.S. Pat. No. 6,503,740 also discloses that, “In order to prepare thebiologically activated organically modified mineral material of thepresent invention, quantities of the mineral or clay substrate materialor resin and quaternary amine material are blended in any suitablemanner, in the proportions defined above, together with preculturedbacteria in an aqueous medium. Blending may be accomplished by variousdevices such as a ribbon blender, extruder or the like. Particularsabout the production of organically modified clays are generally knownin the art and are as outlined in U.S. Pat. No. 4,402,881 issued toAlther, which is incorporated by reference herein in its entirety. Aftersuitable mixing, the resulting material which typically has aslurry-like consistency is dried and either milled to a powder orgranulated.”

U.S. Pat. No. 6,503,740 also discloses that, “During the mixing process,nitrogen supplying nutrients such as standard fertilizer, urea and thelike or carbon/glucose supplying nutrients such as molasses and alcoholcan be incorporated. If necessary, oxygenated material can also beincorporated by including slow-release sources of oxygen such ascalcified seaweed or marl. Trace minerals can also be incorporated.”

By way of further illustration, U.S. Pat. No. 6,786,963, the entiredisclosure of which is hereby incorporated by reference into thisspecification, discloses certain diamide compounds that may be used inthe process of the instant invention. Claim 1 of this patent describes“1. A paving composition comprising a bituminous material and a diamidecompound, wherein: the composition is substantially free of water; andthe diamide compound is represented by: [Figure] if A is hydrogen, B isR2 NHR3NH2; if A is R2NH2, B is R3NH2; R1 is a branched orstraight-chain alkyl or aromatic or alkylaromatic group; and R2 and R3are the same or different and are a branched chain alkyl, straight-chainalkyl, or —R—NH—R, in which R is a branched chain alkyl with about 1 toabout 6 carbon atoms or a straight-chain alkyl with about 1 to about 6carbon atoms.” This patent also discloses that, in its backgroundsection, that “Asphalt compositions have relatively poor adhesion tomineral aggregates in the presence of water. Since the aggregate ispreferentially wetted by water, even if the aggregate is dry at the timeit is blended with the asphalt, the eventual penetration of water intothe composition reaches the aggregate and interferes with the bondbetween the aggregate and the asphalt. The result of this stripping isflaked pavement and potholes. Stripping problems also generally occur ifthe aggregate is poorly dried, if sandy carbonate aggregate containing alarge amount of quartz particles is used, if carbonate aggregate iscovered with dust, or if igneous (silicate) aggregates, such as granite,diorite, gabbro, diabase, or basalt, that strip in the presence ofexternal water are used. To avoid such failures, adhesion-improvingagents known as “anti-stripping agents” are commonly added to theasphalt. Before the mixing operation, these agents are added to thebituminous binder to reduce its surface tension and to induce on thebinder an electrical charge opposite to that of the aggregate surface.Lower surface tension gives improved wettability of the aggregate, andcharge reversal enhances bond strength by increasing Coulomb'sattractive forces.”

U.S. Pat. No. 6,786,963 also discloses that, “Cationic substances,particularly amines, have been traditionally used as anti-strippingagents. The cationic substances increase the hydrophobicity of theaggregate, making the aggregate resistant to the penetration of water sothat water seeping into the asphalt does not tend to destroy the bondbetween the asphalt and the aggregate. The addition of the cationicsubstances tends to make the aggregate sufficiently water resistant thata good bond with the asphalt is formed. Among the cationic materialswhich have been used as adhesion promoters with asphalt, are primaryalkyl amines (such as lauryl amine and stearyl amine) and alkylenediamines (such as the fatty alkyl substituted alkylene diamines).Because these amines may rapidly lose their activity when combined withasphalt and stored at elevated temperatures for an extended period, ithas therefore been necessary to combine the amine with the asphalt atthe work site when the asphalt is combined with the aggregate, which inpractice presents difficulties in obtaining a homogeneous mixture. It isalso noted that these amines are generally corrosive and may have anunpleasant smell.”

U.S. Pat. No. 6,786,963 also discloses that, “Various asphaltformulations have been reported in attempts to enhance the properties ofpaving compositions while avoiding the above-described difficulties.U.S. Pat. No. 4,447,269 offers cationic oil in water type bituminousaggregate slurries. The emulsion comprises bitumen and a reactionproduct of a polyamine and a polycarboxylic acid, and water. Lime orcement can be added to reduce the setting time of the mixture.”

As is also disclosed in U.S. Pat. No. 6,786,963, “U.S. Pat. No.4,721,529 suggests the preparation and use of asphalt admixtures withthe reaction product of an amine antistrip and an acid salt. The acidsalt is a divalent or trivalent metal salt of an inorganic acid. U.S.Pat. No. 5,443,632 suggests cationic aqueous bituminousemulsion-aggregate paving slurry seal mixtures. The emulsifier is theproduct of reaction of polyamines with fatty acids and rosing, and aquaternizing agent. U.S. Pat. No. 4,806,166 proposes preparation of anaggregate comprising asphalt and an adhesion improving amount of ananti-stripping agent comprising the aminoester reaction product of atall oil fatty acid and triethanolamine. The reaction product is of lowviscosity, has good coating performance, and is inexpensive. U.S. Pat.No. 5,019,610 offers an asphalt composition comprising a blend of athermoplastic rubber polymer and a fatty dialkyl amide, and asphaltcement. The preparation method requires only gentle stirring. The amidehas a C6-C22 alkyl group attached to the carbonyl, and two C1-C8 alkylgroups attached to the amide nitrogen. The compositions offer goodviscosities at relatively low residue percentages. The compositions areoffered for use in road paving, asphalt roofing cements, mastics,moisture barriers, joint and crack fillers, and sheeting.”

U.S. Pat. No. 6,786,963 also discloses that “U.S. Pat. No. 4,430,127suggests preparation of a bitumen and epoxylated polyamine composition.The compositions provide improved adhesion between aggregate materialsand the bitumen material. At least two of the amino nitrogen atoms areseparated by six carbon atoms. U.S. Pat. No. 4,462,840 proposes use of acation-active emulsifier which is the product of a polyamine andpolycarboxylic acids. The emulsifier is useful in producing aqueousbituminous emulsion-aggregate slurries.”

By way of yet further illustration, U.S. Pat. No. 6,875,341 describesand claims the use of certain antistrip agents; the entire disclosure ofthis United States patent is hereby incorporated by reference into thisspecification.

Claim 11 of U.S. Pat. No. 6,875,341 describes, “11. A process forextraction of selected heteroatom-containing compounds fromhydrocarbonaceous oil for use in commodity, specialty or industrialapplications, the process comprising contacting the hydrocarbonaceousoil with a mixture of polar solvent and water to selectively recoverheteroatom-containing compounds into an extract fraction that containslow concentrations of non-heteroatom-containing compounds by use of asolvent and water mixture in a ratio to achieve acoefficient-of-separation of heteroatom-containing compounds that isgreater than 65%, where the coefficient of separation is the molepercent of heteroatom-containing compounds from the carbonaceous oilthat are recovered in the extract fraction minus the mole percent ofnon-heteroatom-containing compounds from the carbonaceous oil that arerecovered in the extract fraction.” An antistrip agent made via thisprocess is identified in claim 12, which states, “12. The process ofclaim 11 wherein the extracted fraction containing high concentrationsof heteroatom-containing compounds and low concentrations ofnon-heteroatom-containing compounds is used with little or no furtherprocessing as an antistrip asphalt additive . . . ”. Similarly, claim 13of U.S. Pat. No. 6,875,341 discusses, “13. The process of claim 11wherein the extracted fraction containing high concentrations ofheteroatom-containing compounds and low concentrations ofnon-heteroatom-containing compounds is used as a feedstock formanufacture of surfactants, pyridine N-oxides, quaternary pyridiniumsalts, asphalt antistrip additives . . . ”

By way of yet further illustration, one may use one or more of theantistrip agents disclosed in U.S. Pat. No. 4,839,404 (bituminouscompositions having high adhesive properties), U.S. Pat. No. 4,933,384(bituminous materials), U.S. Pat. No. 4,975,476 (bituminous materials),U.S. Pat. No. 5,352,275 (method of producing hot mix asphalt), U.S. Pat.No. 5,558,702 (asphalt emulsions containing amphoteric emulsifier), U.S.Pat. No. 5,566,576 (asphalt emulsions), U.S. Pat. No. 5,660,498(patching system and method for repairing roadways), U.S. Pat. No.5,667,577 (filled asphalt emulsions containing betaine emulsifier), U.S.Pat. No. 5,755,865 (asphalt rejuvenator and recycled asphaltcomposition), U.S. Pat. No. 5,766,333 (method for recycling andrejuvenating asphalt pavement), U.S. Pat. No. 6,093,494 (antistrip latexfor aggregate treatment), U.S. Pat. No. 6,403,687 (antistrip latex foraggregate treatment), and the like. The entire disclosure of each ofthese United States patents is hereby incorporated by reference intothis specification.

In one preferred embodiment, the antistrip agent is an organic amine,which may be primary, secondary, or tertiary, and which contains fromabout 1 to about 18 carbon atoms.

In one preferred embodiment, the antistrip agent is an amido-amine(fatty acid amine).

In one preferred embodiment, the antistrip agent is comprised of4,4′-methylenebiscyclohexanamine. In another embodiment, the antistripagent is comprised of mixed polycycloaliphatic amines.

In one preferred embodiment, in addition to or instead of the antistripagent, one may use an adhesion-promoting agent, such as, e.g., theadhesion agents described in U.S. Pat. No. 5,240,760, the entiredisclosure of which is hereby incorporated by reference into thisspecification. As is disclosed in this patent (see from line 56 ofcolumn 4 to line 38 of column 5), “Suitable adhesion agents arecompound(s) capable of promoting the adhesion of roofing granules to anasphalt-based substrate. Preferred adhesion agents are hydrophobic innature, and do not significantly alter the color of the roofinggranules. The adhesion agent should be compatible with the polysiloxaneand the roofing granules' surfaces. Preferred adhesion agents aresilicones other than those that have long-chain hydrocarbon groups.Preferred silicones are described in E. Schamberg, Adhesion, v. 29(11),pp. 20, 23-27 (1985), as well as in U.S. Pat. Nos. 4,486,476, 4,452,961,4,537,595 and 4,781,950. These kinds of silicones can be purchased underthe trademark TEGOSIVIN (particularly TEGOSIVIN HL100) from GoldschmidtChemical Corporation, Hopewell, Va.”

U.S. Pat. No. 5,240,760 also discloses that, “Other adhesion agents thatcan be suitable include resin compositions R-20, R-24, R-27, R-270, andR-272, (Union Carbide Corporation, Danbury, Conn.), Wacker SiliconeResins MK, M-62 (Wacker-Chemi GMBA, Alemania, Germany), Dri-Sil™73, DowCorning 1107, Dow Corning 477 Resin (Dow Corning Corporation, Midland,Mich.), SR-82 and SM 2138 available from General Electric, Schenectady,N.Y., and oleic acid, Witco Chemical Corporation, Chicago, Ill. Mixturesor combinations of adhesion agents may be employed.”

U.S. Pat. No. 5,240,760 also discloses that, “The adhesion agent isemployed on the roofing granules' surfaces to an extent sufficient topromote granule adhesion to an asphalt-based substrate. The amount ofadhesion agent can vary depending on the composition of the roofinggranules and adhesion agent. Generally speaking, adhesion agents areemployed at about 0.01 to 5 pounds per ton of roofing granules (5×10⁻⁴to 0.25 weight percent). In the case of TEGOSIVIN silicones noted above,the adhesion agent is preferably applied to the roofing granules atabout 0.5 to 1 lb. per ton of granules (2.5×10⁻³ to 0.05 weightpercent), more preferably at 0.1 to 0.3 pound per ton (0.005 to 0.015weight percent).”

U.S. Pat. No. 5,240,760 also discloses that, “The polysiloxane andadhesion agent are preferably applied to the roofing granules as solutesin an oil solvent. The oil assists in spreading the polysiloxane andadhesion agent to the roofing granules' surfaces, and also helps reducedust formation.”

U.S. Pat. No. 5,240,760 also discloses that, “When using an oil to applythe adhesion agent and polysiloxane to roofing granules' surfaces, theoil is employed at up to about 12 pounds per ton of roofing granules(0.6 weight percent) based on the weight of roofing granules, preferably1 to 10 pounds per ton (0.05 to 0.5 weight percent), and more preferably5 to 8 pounds per ton (0.25 to 0.4 weight percent).”

U.S. Pat. No. 5,411,803, the entire disclosure of which is herebyincorporated by reference into this specification, also describesadhesion agents. As is disclosed in such patent, “Adhesion to bituminoussurfaces is also improved using ZFP and borate compounds. Adhesion isdescribed in terms of wet and dry “pick tests,” which are described indetail in the Test Methods Section. The dry and wet pick values haveunits of percent (%), with a higher number indicating better adhesion, alow number indicating cohesive failure of the bituminous surface towhich the granule is adhered, rather than adhesive failure of thegranule from the surface. Preferred values for dry pick are at leastabout 75%, whereas for wet pick the value is at least about 50%, morepreferably at least about 70%.” (See column 7, lines 3-14.)

Referring again to FIG. 1, and in the preferred embodiment depictedtherein, the antistrip agent (and/or the adhesion agent) is preferablymixed in mixer 36 with the particulate material (from line 34) and,optionally, with an oil, such as, e.g., a naphthenic mineral oil. In oneembodiment, the use of the antistrip agent is omitted, and only the oilis applied as a coating. In another embodiment, the use of the oil isomitted, and only the antistrip agent is applied as a coating. In yetanother embodiment, neither such oil nor such antistrip agent isutilized.

The oil used may be, e.g., a “hydrocarbon oil,” as that term is definedin U.S. Pat. No. 6,358,305, the entire disclosure of which is herebyincorporated by reference into this specification. At column 4 of U.S.Pat. No. 6,358,305, certain “hydrocarbon oils” are described; one ormore of these “hydrocarbon oils” may be used in conjunction with the“antistrip agent” described elsewhere in this specification (or byitself) to prepare coated limestone granules. At lines 47-54 of suchcolumn 4, it is disclosed that, “The hydrocarbon oils employed in thecompositions of the present invention may be either synthetic or naturalin origin. These oils, referred to as process oils, can be obtained frompetroleum, coal, gas and shale. The oils are of the lubricating oilviscosity range, typically in a 300 c.p. viscosity range. Thesehydrocarbon oils are often referred to as process oils and are availablefrom several companies, such as Ergon Inc., Arco and Cross Oil Co.”

Alternatively, or additionally, one may use one or more naphthenicmineral oils. These naphthenic mineral oils contain a significantproportion of naphthenic compounds, and they are well known to thoseskilled in the art. Reference may be had to the following United Statespatents which refer to “napthenic mineral oil” in their claims: U.S.Pat. No. 3,980,448 (organic compounds as fuel additives), U.S. Pat. No.4,101,429 (lubricant compositions), U.S. Pat. No. 4,180,466 (method oflubrication of a controlled-slip differential), U.S. Pat. No. 4,324,453(filling material for electrical and light waveguide communicationscables), U.S. Pat. No. 4,374,168 (metalworking lubrication), U.S. Pat.No. 4,428,850 (low foaming lubricating oil compositions), U.S. Pat. No.4,510,062 (refrigeration oil composition), U.S. Pat. No. 4,676,917(railway diesel crankcase lubricant), U.S. Pat. No. 4,720,350 (oxidationand corrosion inhibiting additives for railway diesel crankcaselubricants), U.S. Pat. No. 4,793,939 (lubricating oil compositioncontaining a polyalkylene oxide additive), U.S. Pat. No. 4,781,846(additives for aqueous lubricant), U.S. Pat. No. 5,460,741 (lubricatingoil composition), U.S. Pat. No. 5,547,596 (lubricant composition forlimited slip differential of a car), U.S. Pat. No. 5,658,886(lubricating oil composition), U.S. Pat. No. 6,063,447 (process fortreating the surface of metal parts), U.S. Pat. No. 6,245,723 (coolinglubricant emulsion), U.S. Pat. No. 6,482,780 (grease composition forrolling bearing), U.S. Pat. No. 6,736,991 (refrigeration lubricant forhydrofluorocarbon refrigerants), and the like. The entire disclosure ofeach of these United States patents is hereby incorporated by referenceinto this specification.

When both the oil and the antistrip agent is used, it is preferred thatthe ratio of the oil/antistrip agent used is from about 10/90 to about90/10 weight percent. In one embodiment, from about 0.25 to about 1.0pounds of such oil is added for each 2,000 pounds of the limestonegranules in mixer 45. In another embodiment, from about 0.25 to about1.0 pounds of a mixture of such oil and one or more of theaforementioned antistrip agent is added for each 2,000 pounds of thelimestone granules in mixer 45.

In another embodiment, from about 1 to about 3 parts of oil arepreferably used for each part of the antistrip compound. In one aspectof this embodiment, from about 1.5 to about 2.5 parts of oil are usedfor each part of the antistrip compound.

In one embodiment, from about 0.5 to about 2.0 gallons of such oil, andfrom about 0.5 to about 1.0 gallons of such antistrip compound are addedfor each ton of the limestone granules.

In one embodiment, a sufficient amount of oil and/or antistrip agent ischarged via line 39 to form a coating on the particulate matter in mixer38 that is from about 200 to about 2,000 nanometers and, preferably,from about 300 to about 1200 nanometers.

In one preferred embodiment, a blend of the oil and the antistripcompound is sprayed onto the limestone granules (from “line 40”) as suchgranules are being transferred through a blending screw. The rate ofaddition is preferably based on the rate of the atomizer as it relatesto the rate of the material being transferred through the blendingscrew.

In one preferred embodiment, and referring again to FIG. 1, from about0.001 to about 4 parts (by weight) of such oil, and from about 0.001 toabout 4 parts (by weight) of such antistrip agent, are charged to mixer38 for each 100 parts of particulate in such mixer. In one aspect ofthis embodiment, less than 2 weight percent of each of the oil and theantistrip agent are used. In another aspect of this embodiment, lessthan 1 weight percent of each of the oil and the antistrip agent areused. In yet another embodiment, less than about 0.5 weight percent ofeach of the oil and the antistrip agent are used.

In one embodiment, the oil and the antistrip agent are preferably mixedin mixer 38 which, in one aspect of this embodiment, is comprised of ablending screw. One may use any of the blending screws known to thoseskilled in the art. Reference may be had, e.g., to U.S. Pat. No.3,881,708 (mixing extruders), U.S. Pat. No. 3,938,469 (apparatus forcoating particulate material with finely divided solids), U.S. Pat. No.5,573,331 (multiple-stage screw for blending materials), and the like.The entire disclosure of each of these United States patents is herebyincorporated by reference into this specification.

Samples may be periodically withdrawn from the mixer 38 via line 42 tobe tested in laboratory 32 and to determine whether the coated particleshave met the specifications for the roofing granules.

In one embodiment, illustrated in FIG. 1, the aforementioned antistripagent and/or oil are charged to mixer 38 via line 39. In thisembodiment, the particles from air flow separator 30 are chargeddirectly via line 34 to mixer 38.

In another embodiment, illustrated in FIG. 1, the particles from airflow separator 30 are charged via line 34 to mixer 36, but a mixture ofpigment and binder is added to mixer 36. The pigmented particlesproduced in mixer 36 are then charged via line 40 to mixer 38, whereinthe antistrip agent and/or oil is added via line 39. Thereafter, theparticles so treated are fed via line 44 to mass flow silo 46.

In one embodiment, the coated particles of this invention are tested todetermine whether they have the required degree of hydrophobicity. Onemay utilize the assembly 100 depicted in FIG. 2 for this purpose.

Referring to FIG. 2, and in the preferred embodiment depicted therein,the assembly 100 tests material for its ability to resist moistureadsorption, in accordance with the procedure described below. Prior toconducting the test, all of the materials and the equipment arepreferably dried until they are substantially moisture free.

Utilizing a 5.5 centimeter round flat bottomed filter case 102 and anaccompanying fitted funnel bottom 104, one may assemble the apparatusdepicted onto a rubber-stoppered Buchner flask 106. In the embodimentdepicted, a rubber disk 108 is preferably disposed on top of the Buchnerflask 106 in order to seal the vacuum applied to such flask.

Referring again to FIG. 2, the vacuum is pulled through port 110 in thedirection of arrow 112 via a vacuum pump (not shown). While a vacuum ispulled on the apparatus via a vacuum pump (not shown), a filter pad 114(such as, e.g., a Whatman 40 gravimetric analysis filter pad) is wettedwith water until it is fully wetted. Thereafter, the vacuum is allowedto remove free moisture from the filter pad.

Thereafter, the flat-bottomed filter case 102 and wetted filter pad areremoved, and any free moisture from the bottom side of the filterassembly is also removed. The assembly is weighed, and the weight isrecorded. Fifty (50) grams of the granular material to be tested isweighed to the nearest 100^(th) of a gram. This material is thentransferred to the filter assembly without moving the filter pad on thebottom of the assembly, and the 50 grams of material are gently tappedto flatten out the sample. Thereafter, 100 grams of distilled water areweighed to the nearest 100^(th) of a gram; and the 100 grams of waterare carefully poured (to avoid causing dimpling of the sample) onto the50 grams of material which has been assembled back onto the top of thefunnel assembly and is under vacuum. The vacuum is allowed to continuepulling the water through the material and through the filter pad. Whenthe water stops coming from the filter (end point is reached when wateris not visible on top of the sample and water has stopped being seen onthe end of the funnel assembly for 30 seconds), the vacuum is broken andthe filter assembly removed from the funnel assembly. Free moisture isthen removed from the bottom of the filter assembly. The filter assemblyand the wet sample are then weighed again, and the weight is recorded.The weight of the final assembly minus the (weight of dry filterassembly and wetted filter+weight of sample) is equal to the amount ofwater adsorbed onto the surface of the sample. This final weight ofabsorbed water is the reported value and can be reported as an absolutevalue or as a percentage of the weight of the sample being tested.

When this test is performed on treated and untreated limestone granulesin the 10-30 mesh range, the untreated limestone will often absorb about2.6 grams of water (which is 4.2 percent of the weight of the 50 gramsample). Some embodiments of the treated limestone, by comparison, willoften absorb only 1.05 grams, which is only 2.1 weight percent of the 50gram sample; other embodiments of the treated limestone have evengreater degrees of hydrophobicity.

It is preferred that the granules of this invention has a hydrophobicityof less than about 3.0 percent and, more preferably, less than about 2.5percent. In one aspect of this embodiment, the granules have ahydrophobicity of less than about 2.0 percent and, more preferably, lessthan about 1.5 percent.

The Moh's Hardness of the Coated Granules

In one embodiment, and referring again to the coated particles producedin mixer 36 of FIG. 1, the Moh's hardness of the coated particles isfrom about 2.5 to about 3.5 and is often from about 2.9 to about 3.1. Itshould be noted that calcite, which is the predominant component oflimestone, is 3.0 on the Moh's scale.

The Adhesion of the Coated Granules

In one preferred embodiment, the adhesion of the coated granules istested in accordance with ASTM Standard test 4977-03. It is to beunderstood that, when reference is made to “adhesion loss as determinedby ASTM Standard test 4977-3,” it is to be understood that such termrefers to the adhesion loss of a shingle made in accordance with thespecified procedure that has been subjected to the specified rub test.This rub test procedure is described elsewhere in this specification.

pH of the Granules

In one embodiment, the pH of the coated particles in mixer 44 and/or 45is from about 8 to about 11 and, more preferably, from about 9 to about11.

Referring again to FIG. 1, after the coated particles in mixer 36 and/or38 have the desired combination of properties, they are conveyed vialine 44 to mass flow silo 46. Such a mass flow silo is well known and isdescribed, e.g., in the claims of U.S. Pat. No. 4,818,117 (apparatus formixing bulk materials in dust, powder, or coarse grained form), U.S.Pat. No. 6,547,948, and the like. The entire disclosure of each of theseUnited States patents is hereby incorporated by reference into thisspecification.

Preparation of a Roofing Shingle

Referring again to FIG. 1, and in one preferred embodiment depictedtherein, in step 56 roofing shingles are prepared with the coatedgranules disposed in mass flow silo 52.

The roofing shingles may be made in accordance with the proceduredescribed in U.S. Pat. No. 3,888,684, the entire disclosure of which ishereby incorporated by reference into this specification; alternatively,such shingle may be made in accordance with the procedure describedelsewhere in this specification.

As is disclosed in United States patent, “The asphaltic roofingcompositions in which the novel algicidal roofing granules of thepresent invention are incorporated are roofing shingles, rolled roofing,and the like, having an organic asphalt-saturated felt base that iscoated with an asphalt of a higher softening point and surfaced withbase mineral granules having the subject inner and outer color coatingsthereon. The felt layer is customarily composed of wood fibers, eitheralone or in combination with paper pulp, repulped paper and/or rags,asbestos fibers, or the like. Such felts are generally referred to inthe industry as roofing felts. The saturants most commonly employed tosaturate the felt layer include residual oil, soft residual asphalt andsoft blown petroleum asphalt, and mixtures thereof. Preferred saturantsgenerally have a ring and ball softening point of approximately 120° to130° F. and a penetration of approximately 60 at 77° F.”

U.S. Pat. No. 3,888,684 also discloses that, “This saturated felt layeris then coated with an asphalt of a higher softening point and lowerpenetration from that of the saturant. Preferred materials willgenerally have a ring and ball softening point of approximately 175° to260° F. and a penetration of approximately 10 to 50 at 77° F. Coatingasphalts of this type include native and sludge asphalts, fatty acidpitches and the like. In accordance with customary practices in the art,this asphalt coating layer is commonly embedded with powdered or fibrousfillers of inorganic or organic origin, such as powdered silica (sand),limestone, slate dust, clay, etc., and mixtures thereof. Uponapplication of the asphalt coating to the saturated felt layer, thecolor coated roofing granules of the invention are applied to theasphalt layer surface, and the resulting roofing surface is then passedthrough suitable rollers and presses, quenched and otherwise treated andhandled in accordance with conventional practice in the roofingindustry.” (See from lines 27-63 of column 12.)

One may use the process disclosed in U.S. Pat. No. 4,274,243 to make theroofing shingle; the entire disclosure of this patent is herebyincorporated by reference into this specification. Claim 1 of thispatent describes, “1. A method of forming a laminated roofing shinglecomprising: (a) providing an indefinite length of asphalt-impregnated,felted material; (b) adhering a coating of mineral granules to at leastone surface of said felted material; (c) cutting said material in arepeating pattern along the longitudinal dimension of said material soas to form an interleaved series of tabs of pairs of overlay members,each said tab, defined by said step of cutting, being of substantiallyidentical shape and the lower edge of each said tab being defined by asmoothly curving negatively contoured edge; (d) making pairs of underlaymembers in a similar manner as above but wherein the lower edges of theunderlay members are defined by a substantially continuously curvingsinuous cut having a uniform periodic shape and amplitude such that eachpair of underlay members thus formed are substantially identical; and(e) laminating said underlay members to said overlay members so as toform a series of shingles having substantially the same overall shape,wherein said step of laminating further includes the step of positioningsaid negatively contoured edge of each said tab directly over asubstantially correspondingly curving portion of the lower edge of eachsaid underlay member so as to simulate a series of alternating ridgesand valleys of a portion of a tile covered roof.”

One may use one or more of the mats described in U.S. Pat. No. 4,634,622to make the roofing shingle; the entire disclosure of such patent ishereby incorporated by reference into this specification. As isdisclosed in such patent, “Asphalt shingles and roll roofing have beenproduced in the same general manner for many years. The industryinitially used an organic fibrous mat or an asbestos fiber mat as thepreformed carrier. Mats of this type contributed significantly to thestrength and flexibility of the finished product. Normally they weresaturated with unfilled asphalt for waterproofing purposes, then coatedwith a thickness of filled asphalt in which a layer of roofing granulessubsequently was embedded. The asphalt layer acted as a furtherwaterproofing layer and held the granules in place. The granules and thefillers in the asphalt layer also protected the asphalt against thedeleterious action of ultraviolet rays.”

U.S. Pat. No. 4,634,622 also discloses that, “Later, the industry beganmoving more to the use of fiberglass mats instead of the conventionalorganic fibrous mats or asbestos fiber mats. Because fiberglass mats aremuch more porous than the previously used mats, this change eliminatedthe need for asphalt saturant. Instead, filled asphalt previously usedonly for the coating layer was now used both to impregnate and to coatthe mat. Thus the properties of the filled asphalt became more critical.In addition to its waterproofing and weather resistant characteristics,the filled asphalt had to contribute more to the strength of theproduct, providing stability against deformation at roof temperaturesand withstanding stresses encountered in the manufacturing process.Also, it had to adequately resist stresses due to handling by workmenand encountered by environmental conditions such as wind loading andthermal stresses.”

U.S. Pat. No. 4,634,622 also discloses that, “The filler which has beenused by the industry is mineral in nature comprised, for example, ofground limestone, silica, slate, trap rock fines, and the like, and ispresent in the asphalt in substantial amounts. Typically, the fillerused in these conventional roofing products has a specific gravity ofbetween about 2.5 and about 3, which is several times more dense thanthe asphalt which it extends or displaces (the specific gravity ofasphalt is about 1.0). Thus a filler content of about 60% by weightyields a filled asphalt having a specific gravity of about 1.7.”

One may use the process described in U.S. Pat. No. 5,411,803 to make theroofing shingle. As is disclosed in such patent, “Bituminous sheetmaterials such as roofing shingles may be produced using the granules ofthe invention. Roofing shingles typically comprise materials such asfelt, fiberglass, and the like. Application of a saturant or impregnantsuch as asphalt is essential to entirely permeate the felt or fiberglassbase. Typically, applied over the impregnated base is a waterproof orwater-resistant coating, such as asphaltum, upon which is then applied asurfacing of mineral granules, which completes the conventional roofingshingle.” (See column 9, lines 47-57.)

Asphalt is preferably used to making the roofing shingles. As isdisclosed on page 71 of George S. Brady et al.'s “Materials Handbook,”Twelfth Edition (McGraw-Hill Book Company, New York, N.Y., 1986),asphalt is “A bituminous, brownish to jet-black substance, solid orsemi-solid, found in various parts of the world. It consists of amixture of hydrocarbons, is fusible and largely soluble in carbondisulfide. It is also soluble in petroleum solvents and turpentine. Themelting points range from 32 to 38 degrees C. Large deposits occur inTrimidad and Venezuela. Asphalt is of animal origin, as distinct fromcoals of vegetable origin. Native asphalt usually contains much mineralmatter; and crude Trimidad asphalat has a composition of about 47%bitumen, 28 clay, and 25 water. Artificial asphalt is a term applied tothe bituminous residue from coal distillation mechanically mixed withsand or limestone.”

Asphalt is also described in the claims of various United Statespatents, such as, e.g., U.S. Pat. No. 3,617,329 (liquid asphalt), U.S.Pat. No. 4,328,147 (roofing asphalt formulation), U.S. Pat. No.4,382,989 (roofing asphalt formulation), U.S. Pat. No. 4,634,622(lightweight asphalt based building materials), U.S. Pat. No. 4,895,754(oil treated mineral filler for asphalt), U.S. Pat. No. 5,217,530(asphalt pavements), U.S. Pat. No. 5,356,664 (method of inhibiting algaegrowth on asphalt shingles), U.S. Pat. No. 5,380,552 (method ofimproving adhesion between roofing granules and asphalt-based roofingmaterials), U.S. Pat. No. 5,382,449 (method of using volcanic ash tomaintain separation between asphalt roofing shingles), U.S. Pat. No.5,511,899 (recycled waste asphalt), U.S. Pat. No. 5,516,573 (roofingmaterials having a thermoplastic adhesive intergace between coatingasphalt and roofing granules), U.S. Pat. No. 5,746,830 (pneumaticgranule blender for asphalt shingles), U.S. Pat. No. 5,776,541 (methodand apparatus for forming an irregular pattern of granules on an asphaltcoated sheet), U.S. Pat. No. 5,795,622 (method of rotating oroscillating a flow of granules to form a pattern on an asphalt coatedsheet), U.S. Pat. No. 6,095,082 (apparatus for applying granules to anasphalt coated sheet to form a pattern having inner and outer portions),U.S. Pat. No. 6,358,319 (vacuum treatment of asphalt coating), U.S. Pat.No. 6,358,319 (magnetic method and apparatus for depositing granulesonto an asphalt-coated sheet), U.S. Pat. No. 6,465,058 (magnetic methodfor depositing granules onto an asphalt-coated sheet), and the like. Theentire disclosure of each of these United States patents is herebyincorporated by reference into this specification.

Means for Generating an Algicide and/or a Bactericide In Situ

In one preferred embodiment, the mineral composition of the presentinvention is comprised of means for producing an algicide or abactericide after being exposed to electromagnetic radiation. Such meansare well known to those skilled in the art.

Such means may exit a “photodynamic action,” i.e., upon irradiation withlight they act as catalysts for the oxidation of various substrates withoxygen. Some of these “photodynamic catalysts” are discussed in column 1of U.S. Pat. No. 4,530,924, the entire disclosure of which is herebyincorporated by reference into this specification. In the third fullparagraph of such column 1, it is disclosed that: “It is known thatcertain dyes, for example eosin, Bengal Rose, methylene blue and others,have a so-called photodynamic action, i.e. on irradiation with light,they act as catalysts for the oxidation of various substrates withoxygen [see, for example, G. O, Schenck, Angew. Chem. 69, 579 (1957)].Because of this property, the said dyes also have a certainantimicrobial action [see, for example, Venkataraman, The Chemistry ofSynthetic Dyes, Volume 4 (1971) pages 502-505 and C. J. Wallis, J. L.Melnick, J. Bacteriol. 89, 41 (1965)].” As is disclosed in column 6 ofsuch patent, the phthalocyanine compounds of this patent developantimicrobial activity upon being irradiated by visible and/or infraredlight. The wavelength of visible light is from about 400 to about 750nanometers. Infrared radiation is the invisible portion of theelectromagnetic spectrum that lies between about 0.75 and 1,000 microns;radiation in the near infrared (from about 0.75 to about 3 microns)produces a sensation of heat.

Such means may be a photocatalyst, as that term is defined in U.S. Pat.No. 5,541,096, the entire disclosure of which is hereby incorporated byreference into this specification. This patent discloses that algae,fungi, and bacteria may be killed when titanium oxy compounds (such astitanium oxides) are exposed to electromagnetic radiation. Thesetitanium oxy compounds (and others) are discussed at column 4 of thepatent, wherein it is disclosed that: “Photosemiconductor particleshaving photocatalytic function include known photocatalysts such astitanium oxy compounds, zinc oxide, tungsten oxide, iron oxide,strontium titanate, molybdenum sulfide, cadmium sulfide, and the like,which can be used alone or in combination of two or more. Particularly,preferred are titanium oxy compounds having a higher photocatalyticfunction, higher chemical stability and being harmless. As used in thepresent invention, the term ‘titanium oxy compounds’ refers to thoseso-called titanium oxide, hydrated titanium oxide, hydrous titaniumoxide, metatitanic acid, orthotitanic acid, titanium hydroxide and thelike, the crystal form of which is not critical. The titanium oxycompounds as above may be produced by any one of a variety of knownmethods . . . ”

By way of further illustration, one may use the photocatalytichydrophilic coating compositions disclosed in U.S. Pat. No. 5,916,947,the entire disclosure of which is hereby incorporated by reference intothis specification. This patent discloses that, when exposed to visiblelight, “aqueous aerated solutions containing zinc oxide pigment leads tothe formation of hydrogen peroxide only when exposed to ultravioletlight of wavelengths greater than 400 nm . . . ” (see columns 1-2). Bycomparison, when exposed to “visible light” (i.e., electromagneticradiation detectable by the eye, ranging in wavelength from about 400 toabout 740 nanometers), the zinc oxide composition of this patent becometoxic to life. This composition is described, e.g., in claim 1 of suchpatent, which describes: “1. A material useful for producing antifoulingactivity when incorporated into a carrier comprising: about between 20wt. % and 60 wt. % of the total material weight of zinc oxide containingless than about 0.001% by weight of lead, cadmium and sulphur oxides andbeing obtained from colloidal zinc oxide so as to have a mean particlesize of between 0.1 to 0.5 microns and a surface area between 1 to 10square meters per gram; a photosensitizer in photoelectric contact withzinc oxide and being present in a ratio of one part by weight or less ofphotosensitizer to four parts by weight zinc oxide, said photosensitizerhaving a solubility below five parts per million by weight in water andwherein said photosensitizer is surface coated onto said zinc oxide andis selected from the group consisting of fumed anatase, strontiumtitanate, bianthrone, azulene, zinc pyrithione, terthiophene, hypericinand mixtures thereof.”

In one embodiment, the toxic agent precursor used in the mineralcomposition of this invention produces a toxic agent when subjected toelectromagnetic radiation. As used herein, the term electromagneticradiation refers to radiation emitted from vibrating charged particles.As is known to those skilled in the art, a combination of oscillatingelectrical and magnetic fields propagates through otherwise empty spacewith the velocity of light; the constant velocity equals the alternationfrequency multiplied by the wavelength. Reference may be had, e.g., toU.S. Pat. No. 5,374,405 (rotating fluidized bed reactor withelectromagnetic radiation source), U.S. Pat. No. 5,686,178 (metal coatedsubstrate articles responsive to electromagnetic radiation), U.S. Pat.No. 6,183,727 (use of long wavelength electromagnetic radiation), U.S.Pat. No. 6,369,399 (electromagnetic radiation shielding material anddevice), U.S. Pat. No. 6,616,451 (electromagnetic radiation emittingtoothbrush), U.S. Pat. No. 6,654,627 (method and device for recordingpolarized electromagnetic radiation of inactivated strain of pathogenicmicroorganisms), and the like. The entire disclosure of each of theseUnited States patents is hereby incorporated by reference into thisspecification.

One may use the titanium oxide toxic agent precursor disclosed in U.S.Pat. No. 6,291,067, the entire disclosure of which is herebyincorporated by reference into this specification. In column 1 of suchpatent, it is disclosed that: “When titanium oxide is irradiated withlight, an electron having a strong reducing action and a positive holehaving a strong oxidizing action are generated and a molecular seedcoming into contact therewith is decomposed by the oxidation-reductionaction. Using such an action, namely, photocatalytic action of titaniumoxide, organic solvents dissolved in water, environmental pollutantssuch as agricultural chemicals and surface active agents, or harmfulsubstances in air or malodors can be decomposition-removed. This methodutilizes only titanium oxide and light and can be repeatedly used, andmoreover, the resulting reaction product is a harmless carbon dioxide orthe like.” Claim 1 of this patent describes: “1. An organic polymerfiber having an environmental clarification function, which hassupported thereon a photocatalytic powder for environmentalclarification, said powder comprising finely divided titanium dioxideparticles having a coating of porous calcium phosphate formed on atleast part of the surface of each finely divided titanium dioxideparticle, wherein an anionic surface active agent is present at least onthe interface between said coating of porous calcium phosphate and thefinely divided titanium dioxide particle.” In the experiments describedin the Examples of such patent, and ultraviolet light source (i.e., asource of electromagnetic radiation with a wavelength of from about 1 toabout 400 nanometers) was used.

One may use one of the “oxygen molecule absorbing/desorbing” agentsdisclosed in U.S. Pat. No. 6,294,247, the entire disclosure of which ishereby incorporated by reference into this specification. As isdisclosed in column 1 of this patent, “TiO₂, V₂O₅, ZnO, WO₃, etc. haveheretofore been known as substances which, when irradiated byultraviolet radiation, cause oxygen molecules to be adsorbed to ordesorbed from an organic compound such as a smelly constituent forpromoting decomposition (oxidation) of the organic compound . . . . Forphotocatalytic particles such as TiO₂ particles to function effectivelyas a photocatalyst, it is necessary that the photocatalytic particles beirradiated with ultraviolet radiation and held in contact with asubstance to be decomposed thereby such as a smelly gas or the like.”

One may use a titanium dioxide photocatalyst having a monoclinic crystalstructure that is disclosed in U.S. Pat. No. 6,306,796, the entiredisclosure of which is hereby incorporated by reference into thisspecification. Claim 1 of this patent describes: “1. A titanium dioxidephotocatalyst having a monoclinic crystal structure; wherein saidphotocatalyst is irradiated with light of a wave length which has energygreater than a band gap of the photocatalyst.” The materials that aredegraded by the photocatalyst of this patent are described in column 2of the patent and include: “Examples of deleterious materials which aredecomposed or oxidized by photocatalytic reaction by use of titaniumoxide and then removed, are materials having adverse effect upon humanbody and living environment, and materials which might have such adverseeffect. For instance, there are a variety of biochemical oxygen demandmaterials; environmental pollution materials such as air pollutionmaterials; materials of various agricultural chemicals such asherbicide, bactericide, insecticide and nematocide; and microorganismsuch as bacteria, actinomyces, funguses, algaes and molds. Examples ofenvironmental pollution materials are organic halogen compounds, organicphosphorus compounds, other organic compounds, and inorganic compoundssuch as nitrogen compounds, sulfur compounds, cyanide and chromiumcompounds. Examples of organic halogen compounds are polychlorinatedbiphenyl, fleon, trihalomethanes, trichloroethylene, andtetrachloroethylene. Examples of organic compounds other than organichalogen compounds and organic phosphorous compounds are surface activeagents, hydrocarbons such as oils, aldehydes, mercaptans, alcohols,amines, amino acid, and protein. Examples of nitrogen compounds areammonia and nitrogen oxide.”

One may use a crystalline toxic agent precursor such as, e.g., thecrystalline titania disclosed in U.S. Pat. No. 6,362,121, the entiredisclosure of which is hereby incorporated by reference into thisspecification. Claim 1 of such patent describes: “1. A substrateprovided, on at least a portion of one of its faces, with a coating witha photocatalytic property based on titanium dioxide which exhibits anexternal hydrophilic surface, which is at least partially crystallineand which is incorporated in said coating partly in the form ofparticles predominantly crystallized in the anatase form, said particlesbeing incorporated in the coating using an inorganic binder in the formof an amorphous or partially crystalline silicon oxide or a mixture ofoxides comprising silicon oxides.”

One may use one or more of the photocatalysts described in U.S. Pat. No.6,368,668, the entire disclosure of which is hereby incorporated byreference into this specification. A process for producing at least someof these photocatalysts is described in claim 1 of such patent, whichdiscloses: “1. A process for producing a functional material havingphotocatalytic activity, comprising the steps of: coating aphotocatalyst coating composition comprising a photocatalytic metaloxide and/or a precursor of the photocatalytic metal oxide onto thesurface of a substrate; and rapidly heating the surface of the coatedsubstrate to fix the photocatalytic metal oxide onto the surface of thesubstrate, characterized in that: the rapid heating is carried out by aheating means provided with a heating element having a heating value perunit area of not less than 120 MJ/m2 hr, and the distance between theheating element and the surface of the substrate is 5 to 300 mm, and therapid heating is carried out for 2 to 60 seconds.”

One may use the ultrafine titanium dioxide powder disclosed in U.S. Pat.No. 6,383,980 to produce an algicidal agent; the entire disclosure ofthis patent is hereby incorporated by reference into this specification.This material is described in claim 1 of such patent, and it discloses:“1. A photocatalytic titanium dioxide powder comprising finely dividedtitanium dioxide particles each having supported on the surface thereofa first supported layer comprising a calcium compound, and furtherhaving supported on the surface of said first supported layer-formedtitanium dioxide particle a porous second supported layer comprising aphotocatalytically inactive and substantially water-insolublesubstance.”

One may use the pyrrole photosensitizer disclosed in U.S. Pat. No.6,454,951, the entire disclosure of which is hereby incorporated byreference into this specification. Claim 1 of this patent describes: “1.A composition comprising a solid carrier and more than onephotosensitizer comprising a tetrapyrrole and/or tetraazapyrrolecompound, wherein the carrier is swellable in water and is selected fromthe group consisting of polystyrol, sephadex and clay, and wherein themore than one photosensitizer are chemically bonded to the carrier, havedifferent absorption maxima, and are selected such that the entirespectrum of visible light is utilized for photosensitization.” As isdisclosed in columns 1 and 2 of such patent, such photosensitizer can beused to kill algae, yeast, fungi, germs, etc. As is disclosed in suchcolumn 1, “the terms, ‘germs and/or microorganisms’ relate to microbes,especially microbes which can be pathogeneous, as e.g. gram-positive,gram-negative bacteria, algae, yeast and fungi, wherein said germs canbe present alone or in combination with other microorganisms.”

One may utilize the photocatalytic composition disclosed in U.S. Pat.No. 6,683,023, the entire disclosure of which is hereby incorporated byreference into this specification. In column 1 of this patent, it isdisclosed that many of the prior art algicides and bactericides inaddition to killing pathogens, also attacks the organic material inwhich it is disposed. It is disclosed in such column 1 that: “In recentyears, photocatalytic fine particles using titanium dioxide areattracting attention as an environmental cleaning material forantimicrobial, deodorization, antifouling, air cleaning, water cleaningand the like. The photocatalytic mechanism of titanium dioxide isconsidered attributable to the following mechanism. Upon irradiation oflight on a titanium dioxide fine particle, an electron and a hole aregenerated inside the titanium dioxide fine particle, which reacts withwater or oxygen in the vicinity of the surface of a titanium dioxidefine particle to generate hydroxy radical or hydrogen peroxide. As aresult, strong oxidation reduction activity of this hydroxy radical orhydrogen peroxide, harmful organic substances are decomposed into carbondioxide and water, and thereby cleaned. Such photocatalytic activity ofa titanium dioxide fine particle is thought to semipermanently continueas long as a titanium dioxide fine particle, light, water and oxygen arepresent.”

U.S. Pat. No. 6,683,023 also discloses that: “By taking advantage ofthis photocatalytic property of titanium dioxide, as a representativeapplication example, titanium dioxide fine particles are being kneadedinto an easily handleable medium, such as fiber or a plastic moldedarticle, or into a coating on the surface of a substrate, such as clothor paper. However, decomposition or deterioration by the strongphotocatalytic activity of titanium dioxide readily occurs not only onharmful organic materials or environmental pollutants but also on themedium itself such as fiber, plastic or paper and this is an obstacle todurability in practical use. Due to easy handleability of the titaniumdioxide fine particle, a coating material comprising a mixture oftitanium dioxide fine particles and a binder has been developed.However, an inexpensive binder having durability sufficiently high toovercome, for example, decomposition or deterioration on the medium hasnot yet been found.

U.S. Pat. No. 6,683,023 also discloses that: “JP-A-9-225319 (the term“JP-A” as used herein means an “unexamined published Japanese patentapplication”) and JP-A-9-239277 disclose means for preventing andsuppressing the deterioration of a resin medium or the deterioration ofa binder due to the strong photocatalytic activity of titanium dioxideparticles. The proposed means is a method of allowing a photo-inactivecompound having such as aluminum, silicon and zirconium to be supportedon a titanium dioxide particle in an archipelago shape having a stericbarrier to retard the photocatalytic activity. According to this method,the photo-inactive compound is supported in an archipelago shape;however, specific sites of the resin medium or the binderdisadvantageously remain present under the strong photocatalyticactivity of titanium dioxide.”

U.S. Pat. No. 6,683,023 also discloses that: “International PublicationWO99/33566 discloses a powder material of titanium dioxide fineparticles, where a porous coating layer of calcium phosphate is formedon at least a part of the surface of a titanium dioxide fine particleand an anionic surfactant is present at the interface therebetween.”

U.S. Pat. No. 6,683,023 also discloses that: “With respect to a slurrycontaining titanium dioxide having photocatalytic activity,JP-A-10-142008 discloses an anatase-type titanium oxide-containingslurry which is obtained by heat-treating a titania sol, a titania gelform or a titania sol-gel mixture in a closed vessel simultaneously witha pressurization treatment and then dispersing using an ultrasonic waveor stirring the treated product.”

U.S. Pat. No. 6,683,023 also discloses that: “JP-A-11-343426 discloses aphotocatalytic coating material having excellent dispersion stabilityand specifically discloses a photocatalytic coating material containing,in a solvent, a silica sol and titanium oxide having a Raman spectrumpeak in the range of 146 to 150 cm⁻¹ and being occupied by anatase typetitanium dioxide in a ratio of 95% by mass or more.”

One may coat the mineral composition of this invention with aphotocatalytic coating such as, e.g., the coating described in claim 1of U.S. Pat. No. 6,700,066, the entire disclosure of which is herebyincorporated by reference into this specification. Claim 1 of thispatent describes: “1. A coated substrate prepared by a processcomprising: (a) preparing a substrate for deposition with a coating,wherein the coating comprises crystallized particles of an oxide of ametal A having photocatalytic properties, a mineral binder comprising atleast one oxide of a metal B having photocatalytic properties,optionally at least one oxide of a metal M devoid of photocatalyticproperties, and optionally at least one silicon oxide; (b) depositingthe coating onto a surface of the substrate, by depositing the coatingfrom liquid-phase dispersions containing oxides of the metals A and B,optionally the oxide of metal M and optionally the silicon oxide, in arelative proportion by weight of the metals and Si given by A/(B+M+Si),the relative proportion ranging from 60/40 to 40/60; and (c) allowingthe coating to set.”

The coatings of U.S. Pat. No. 6,720,066 provide both photocatalyticperformance and durability. As is disclosed in column 2 of such patent,“The present invention has allowed the simultaneous optimization of twocoating properties, photocatalytic performance and coating durability,which previously appeared to be incompatible.”

One may use a photocatalytic material having titanium oxide crystals andanions X incorporated therein, as is disclosed in U.S. Pat. No.6,794,065, the entire disclosure of which is hereby incorporated byreference into this specification. Claim 1 of this patent discloses: “1.A photocatalytic material exhibiting a photocatalytic action whenexposed to light with a wavelength in the region of ultraviolet lightand visible light, comprising a titanium compound Ti—O—X obtained by atleast one of: substituting an anion X for a plurality of oxygen sites oftitanium oxide crystals, doping an anion X between lattices of atitanium oxide crystal, and doping an anion X in grain boundaries oftitanium oxide aggregate.” In column 1 of this patent, a discussion ispresented as to why most titania materials exhibit photocatalyticactivity only in the ultraviolet range. It is disclosed that: “Hitherto,known materials exhibiting a photocatalytic action include the likes ofTiO2 (titanium dioxide), CdS (cadmium sulfide), WO3 (tungsten trioxide),and ZnO (zinc oxide). These photocatalytic materials are semiconductors,absorb light to form electrons and holes, and present various chemicalreactions and bactericidal actions. However, because titanium oxide isnontoxic and is superior from the standpoint of stability to water andacid, so far only titanium oxide has been put to practical commercialuse as a photocatalyst.”

U.S. Pat. No. 6,794,065 also discloses that: “However, because of thevalues of the band gap (Eg=3.2 eV) of titanium oxide, the operatinglight of such a titanium oxide photocatalyst is limited to ultravioletlight with a wavelength .lambda.<380 nm. As a consequence, there remainsan unfulfilled demand for development of materials which exhibitcatalytic activity when irradiated with visible light with a wavelengthof 380 nm or longer. These materials are desired, for example, for useindoors and for improving photocatalytic activity.”

U.S. Pat. No. 6,794,065 also discloses that: “As described in JapanesePatent Laid-Open publication No. Hei 9-262482, by modifying materialsusing ion implanting of metal elements such as Cr (chrome) and V(vanadium) in anatase type titanium oxide having a high catalyticactivity, the light absorbing edge of titanium oxide can be shifted tothe long wavelength side to permit the operation of titanium oxidecatalyst in visible light. No reports discussing the doping of Cr, V,and so on have been published since the early 1970s which succeeded inoperating under visible light. Japanese Patent Laid-Open publication No.Hei 9-262482 describes that operation under visible light can be enabledthrough use of special techniques for doping Cr, V, and so on. Thus, inthe above conventional example, the operation of TiO2 photocatalystunder visible light is made possible by a technique of ion implantingmetal elements in TiO2. However, metal ion implantation isdisadvantageous because of its high cost. While there is a demand formethods for manufacturing TiO2 photocatalyst, such as by synthesis insolution or by sputtering, when these methods are employed, theresulting photocatalysts can not be operated under visible light. It isgenerally considered that this is because Cr of the dopant aggregates orforms oxides such as Cr2 O3 in a crystallization process. Thus, in theconventional examples, there is a problem that a technique of ionimplanting metal elements must be adopted in order for metal elements tobe used to enable operation of TiO2 under visible light.”

One may use a photocatalytic material that is activated by visible lightsuch as, e.g., the material disclosed in U.S. Pat. No. 6,835,688, theentire disclosure of which is hereby incorporated by reference into thisspecification. As is disclosed in column 1 of this patent,“Conventionally known materials exhibiting a photocatalytic actioninclude TiO2 (titanium dioxide), CdS (cadmium sulfide), WO3 (tungstentrioxide), and ZnO (zinc oxide), for example. These photocatalyticmaterials are semiconductors, absorb light to form electrons and holes,and also promote various chemical reactions and bactericidal actions.However, because titanium oxide is nontoxic and exhibits a superiorstability to water and acid, thus far, only titanium oxide has affordedpractical commercial use as a photocatalyst. However, because of thevalues of the band gap (Eg=3.2 eV) of titanium oxide the operating lightof such a titanium oxide photocatalyst is limited to ultraviolet lightwith a wavelength .lambda.<380 nm. As a consequence, an unfulfilleddemand exits for materials which exhibit catalytic activity whenirradiated with visible light having a wavelength of 380 nm or longer.These materials are desired, for example, for use indoors and forimproving photocatalytic activity.”

U.S. Pat. No. 6,835,688 also discloses that: ‘As described in JapanesePatent Laid-Open publication No. Hei 9-262482, by modifying materialsusing ion implanting of metal elements such as Cr (chromium) and V(vanadium) in anatase type titanium oxide having a high catalyticactivity, the light absorbing edge of titanium oxide can be shifted tothe long wavelength side to permit the operation of titanium oxidecatalyst in visible light. Although a number of reports discussing thedoping of Cr, and V, for example, on have been published since the early1970s, these reports describe, however, that in instances whereoperation under visible light is enabled, the performance of thetitanium oxide sharply lowers. On the other hand, as described inJapanese Patent Laid-Open publication No. Hei 9-262482, the originalperformance of titanium oxide can be maintained through use of specialtechniques for doping Cr, and V, for example. Thus, in the aboveconventional example, the operation of titanium oxide photocatalystunder visible light is made possible by ion implantation of metalelements in titanium oxide.’

A Durable Means for Inhibiting the Growth of Algae and Bacteria

In this section of the specification, one preferred means for inhibitingthe growth of algae and bacteria will be described. The material used inthis embodiment will provide long term durability to the mineralcompositions and to the articles (such as shingles) into which suchmaterial is incorporated.

Another Preferred Process for Making Headlap Granules

FIG. 4 is a partial schematic of a process 400 for preparing coatedheadlap particles. Supply tank 402 contains oil such as, e.g., thenapthenic mineral oil described elsewhere in this specification. Supplytank 404 contains antistrip agent such as, e.g., the amine antistripagent disclosed elsewhere in this specification.

The oil used in supply tank 402 preferably has a viscosity, underambient conditions, of from about 70 to about 300 centipoise and, morepreferably, from about 80 to about 120 centipoise.

The oil from tank 402 is pumped by pump 406 to mixing tank 412. Theantistrip agent from tank 404 is pumped by pump 408 to mixing tank 412.The flow rates of these materials are adjusted so that the correct ratioof oil/antistrip agent is present in mixing tank 412. This ratio, in oneembodiment, is from about 2.5 to about 3.5.

It is preferred to maintain a substantially homogeneous mixture of theoil and the antistrip agent in mixing tank 412.

In order to maintain the mixture in tank 412 at the desired properties,the mixture is preferably continuously stirred with mixer 414 and heatedwith immersion heater 416.

The heated mixture from mixing tank 412 may be fed to coating pump 420and/or coating pump 422. Oil from oil tank 410 may be added to themixture that is fed to coating pump 420 and/or coating pump 422.Alternatively, or additionally, oil from oil tank 410 may be fed fromcoating pump 422, and the mixture may then be fed through valves 424 and426 to coating screw 438.

In the embodiment illustrated in FIG. 4, the heated mixture of oil andantistrip agent is fed through metering pump 428 and flowmeter assembly430, and thereafter it is sprayed onto the coating screw 438 which isconveying particles of limestone from classifier 432. The limestoneparticles from classifier 432 are fed into airlock 434 and thence intothe coating screw 438.

EXAMPLES

The following examples are used to illustrate the claimed invention butare not to be deemed limitative thereof. Unless otherwise specified, allparts are by weight, and all temperatures are in degrees Celsius.

In each of the following examples, roofing granules were used to make asample shingle, and the sample shingle was then tested for granuleadhesion in accordance with ASTM Standard Test 4977-3. The procedure formaking the test samples is described hereinbelow.

The test samples used to determine the adhesive characteristics of thecoated limestone granule particles were constructed using apetroleum-based roofing asphalt manufactured by the Hunt RefiningCompany of Tuscaloosa, Ala. This asphalt had been oxidized by blowingwith air at a temperature of approximately 500 degrees Fahrenheit, toachieve a final Ring & Ball Softening Point of 215 degrees Fahrenheit(as determined by ASTM D 36) and had a Needle Penetration of between 15decimillimeters at 77 degrees Fahrenheit (as determined by ASTM D 5).The asphalt product produced after the oxidation is hereinafter referredto as “asphalt shingle coating.”

The viscosity of the asphalt shingle coating was determined inaccordance with ASTM D 4402 at three different temperatures. Theviscosities were 2558 centipoise at 350 degrees Fahrenheit, 500centipoise at 400 degrees Fahrenheit and 189 centipoise at 450 degreesFahrenheit.

A finely divided limestone filler, “grade 85-200 mesh shingle filler,”was obtained from the Franklin Industrial Minerals Company Nashville,Tenn. This filler was blended with the “asphalt shingle coating” to afinal level of 65 weight percent filler. This blended material isreferred to hereinafter as “filled asphalt coating,” and it had a finalRing & Ball Softening Point of 251 degrees Fahrenheit (as determined byASTM D 36) as well as a Needle Penetration of 6 decimillimeters at 77degrees Fahrenheit (as determined by ASTM D 5).

The viscosity of the “filled asphalt coating,” as determined by ASTM D4402, was 6517 centipoise at 400 degrees Fahrenheit, 1867 centipoise at450 degrees Fahrenheit, and 1133 centipoise at 475 degrees Fahrenheit.

The “filled asphalt coating” was then applied to a commerciallyavailable bonded non-woven glass roofing fabric with a dry weight ofapproximately 1.68 pounds per one hundred square feet. This fabricconsisted of sized individual “E” Glass filaments of 15.25-16.5 micronsin diameter (“M” fiber) and from 0.75-1.25 inches in length, which arerandomly oriented and bonded with a modified urea-formaldehyde resinbinder, which has been applied to a level of 20.8% (dry weight). Thisfabric was obtained from the Johns Manville Corporation of Denver, Colo.

The aforementioned glass fabric was coated on each side and saturatedthroughout with the aforementioned “filled asphalt coating” at atemperature of 425 degrees Fahrenheit by using a squeegee to force thecoating into the glass fabric. After the glass fabric had been fullysaturated with the “filled asphalt coating,” 60 mils of such “filledasphalt coating” were applied to the top side of each sample sheet toform a coating. Thereafter, granule particles were sprinkled onto thecoating as described hereinbelow.

Samples of treated, untreated and control granule particles produced forthese experiments were immediately sprinkled on the top surface of thewarm sheet(s); the granules were applied within no more than 5 minutesafter the coating was applied. The granule particles were then rollpressed into the coated glass sheet using a 10 pound roller. Therolled-pressed samples were then allowed to cool to ambient temperatureand thereafter were used for the adhesion experiments describedhereinbelow.

After the finished sheets were cooled to ambient temperature, they werethen cut into 2 inch by 9 inch sample specimens for further “rub-losstesting” in accordance with ASTM D 4977-03. Prior to such “rub-losstesting,” loose granule particles were removed from the samples bygentle tapping of the specimens.

At least two sample specimens were cut for each trial variant, with thelong dimension of the specimen in the machine direction or press-rolldirection. Specimens were conditioned at room temperature of 73.4degrees Fahrenheit plus or minus 3.6 degrees Fahrenheit) for at least 30minutes before testing. Granule abrasion tests were conducted using aGranule Test Apparatus as described in ASTM Procedure D 4977-03. Allloose granules were removed from the specimens by gentle tapping of thesample. Each specimen was weighed to the nearest 0.01 grams and a recordwas made of the initial weight of the specimen. The specimen wascentered in the sample holder of the Test Apparatus with the mineralsurface facing up and the long axis of the specimen aligned with thebrush stroke of the Test Apparatus. The Test Apparatus was activatedsuch that the specimen was abraded 50 complete cycles, each cycleconsisting of a forward stroke and a back stroke, with the brush travelremaining parallel to the long axis of the specimen. The specimen wasremoved from the sample holder and any loose granules were removed fromthe sheet by gently tapping the sample. The specimen was weighed to thenearest 0.01 grams and a record was made of the final weight of thespecimen. The difference in weights for multiple samples of the samespecimen were calculated and averaged to determine the average granuleloss by abrasion.

Examples 1-11

In the experiments described in Examples 1-11, ten different variants oftreated limestone granule shingle specimens and one control specimenwere tested upon completion of the fabrication of the test samples andafter one week of moist storage to determine the relative granulerub-loss amounts under ASTM D-4977-03. For each set of conditions, rubloss results are reported for both un-aged samples, and aged samples(the aged samples being those that had been subjected to a water quenchand stored in an un-dried state for one week.).

The limestone roofing granules used in these experiments of Examples1-11 were obtained from the Franklin Industrial Mineral Corporation ofNashville Tennessee as “limestone headlap granules.” They had a particlesize distribution such that at least about 80 weight percent of saidgranules had sizes in the range of from about 600 to about 1400 microns,and less than about 4 weight percent of said headlap granules weresmaller than 250 microns. These limestone granules were produced at theAnderson, Tenn. plant of the Franklin Industrial Mineral Corporation insubstantial accordance with the procedure described elsewhere in thisspecification.

In the experiment of Example 1, the headlap granules were coated with0.5 gallons per ton of a 50/50 mixture of an amido amines sold as“AD-HERE” LOF 6500″ (sold by Arr Maz Custom Chemicals, Inc. ofWinterhaven, Fla.) and “HYPRENE 100” naphthenic oil sold by ErgonRefining, Inc. of Jackson, Miss. This oil had a viscosity of from 100 to115 Saybolt Universal Seconds (SUS), as measured by ASTM D445, anAmerican Petroleum Institute (API) gravity at 60 degrees Fahrenheit of24.6 (as measured by ASTM D1260), and a Cleveland Open Cup (COC) flashpoint of between 325 and 340 degrees Fahrenheit (as measured by ASTMD92). The un-aged sample produced with these headlap granules had a rubloss of 4.8 grams and the aged sample had a rub loss of 4.4 grams.

In the experiment of Example 2, the same mixture was used as specifiedin Example 1, but the application rate was 1.0 gallon per ton ratherthan 0.5 gallons per ton. The un-aged sample produced with these headlapgranules had a rub loss of 4.5 grams, and the aged sample had a rub lossof 4.2 grams.

In the experiment of Example 3, the same mixture was used as specifiedin Example 1, but the application rate was 1.5 gallons per ton ratherthan 0.5 gallons per ton. The un-aged sample produced with these headlapgranules had a rub loss of 3.8 grams, and the aged sample had a rub lossof 4.3 grams.

In the experiment of Example 4, the “AD-HERE” LOF 6500″ was replacedwith “AD-HERE” LOF 6500LS” amido-amine that was also obtained from ArrMaz Custom Chemicals, Inc. of Winterhaven, Fla. and was also applied asa 50/50 mixture at an application rate of 0.5 gallons per ton. Theun-aged sample produced with these headlap granules had a rub loss of4.7 grams, and the aged sample had a rub loss of 4.3 grams.

In the experiment of Example 5, the same mixture used in Example 4 wasused, but the application rate was 1.0 gallon per ton. The un-agedsample produced with these headlap granules had a rub loss of 4.5 grams,and the aged sample had a rub loss of 4.7 grams.

In the experiment of Example 6, the same mixture used in Example 4 wasused, but the application rate was 1.5 gallons per ton. The un-agedsample produced with these headlap granules had a rub loss of 4.9 grams,and the aged sample had a rub loss of 5.1 grams.

In the experiment of Example 7, the same amido-amine was used, but noneof the oil was used. The application rate was 1 gallon per ton of suchamine. The un-aged sample produced with these headlap granules had a rubloss of 4.4 grams and the aged sample had a rub loss of 4.9 grams.

In the experiment of Example 8, the same oil was used, but none of theamido-amine was used. The application rate was 1 gallon per ton of suchoil. The un-aged sample produced with these headlap granules had a rubloss of 4.2 grams and the aged sample had a rub loss of 4.4 grams.

In the experiment of Example 9, the mixture described in Example 1 wasused at an application rate of 1.75 gallons per ton. The un-aged sampleproduced with these headlap granules had a rub loss of 3.7 grams.

In the experiment of Example 10, the mixture of Example 1 was used at anapplication rate of 2.0 gallons per ton. The un-aged sample producedwith these headlap granules had a rub loss of 4.6 grams.

In the control experiment of Example 11, neither such oil nor an amine(or other anti-strip agent) was used. The un-aged sample produced withthese headlap granules had a rub loss of 4.8 grams, and the aged samplehad a rub loss of 4.2 grams.

Although applicants do not wish to be bound to any particular theory, itis believed that the combination of the oil and the antistrip agent usedin coating the headlap granules produces an unexpected, beneficialresult.

Although the experiments of Examples 1-3 and 9-10 used a 50/50 mixtureof amido-amine and oil, other mixtures will produce comparable results.Thus, from about 10 to 90 weight percent of the oil may be mixed withfrom about 90 to about 10 weight percent of the amine.

In one embodiment, more than one amine antistrip agent is used. Inanother embodiment, more than one oil is used. In yet anotherembodiment, one or more non-amine antistrip agents are used. In yetanother embodiment, one or more non-naphthenic oils are used.

Preparation of Headlap Granules

In one preferred process, headlap granules are prepared that have one ormore of the properties described elsewhere in this specification and, inaddition, contain a tinting agent that preferably comprises a pigmentand a binder.

In this embodiment, the headlap granules preferably comprise at leastabout 0.1 weight percent of the tinting agent and, more preferably, fromabout 0.1 to about 0.8 weight percent of such tinting agent. In oneaspect of this embodiment, the headlap granules comprise from about 0.1to about 0.6 weight percent of the tinting agent. In another aspect ofthis embodiment, the headlap granules comprise from about 0.15 to about0.45 weight percent of the tinting agent. In yet another aspect, fromabout 0.2 to about 0.4 weight percent of the tinting agent is present inthe headlap granules.

In one aspect of this embodiment, the tinting agent is present as acoating on the surfaces of the headlap granules; preferably the coatinghas a thickness of from about 5 to about 15 microns.

In one embodiment, the tinting agent is comprised of from about 10 toabout 35 weight percent of a pigment; in another embodiment, the tintingagent is comprised of from about 10 to about 20 weight percent of apigment. As is known to those skilled in the art, a pigment is asubstance, often in the form of a dry powder, that imparts color toanother substance.

In one embodiment, the pigment is an inorganic pigment. The inorganicpigments may comprise metallic oxides (such as iron, titanium, zinc,cobalt, chromium, etc.), metal powder suspensions (gold, aluminum,etc.), earth colors (siennas, ochers, umbers, etc.), lead chromates,carbon black, etc. Reference may be had, e.g., to U.S. Pat. No.3,839,064 (inorganic pigment-loaded polymeric microcapuslar system),U.S. Pat. No. 3,925,095 (free-flowing dispersible inorganic pigment offiller compositions containing hydroxyalkylate alkylene diamines), U.S.Pat. No. 3,930,101 (inorganic pigment-loaded polymeric microcapsularsystem), U.S. Pat. No. 4,013,617 (process for the manufacture ofhydrophilic polyolefin fibers containing inorganic pigment), U.S. Pat.No. 4,075,029 (inorganic pigment comprising a solid solution ofdiffering spinels), U.S. Pat. No. 4,167,417 (fluorescent inorganicpigment), U.S. Pat. No. 4,202,702 (inorganic pigment comprising a solidsolution of differing spinels), U.S. Pat. No. 4,269,760 (fine sphericalpolymer particles containing inorganic pigment and/or coloring agent andprocess for the preparation thereof), U.S. Pat. No. 4,293,478 (processfor producing polyphenylene ether composition containing inorganicpigment), U.S. Pat. No. 4,334,933 (process for preparing stableinorganic pigment), U.S. Pat. No. 4,349,389 (dispersible inorganicpigment), U.S. Pat. No. 4,818,783 (method for production of aqueousdispersion of inorganic pigment), U.S. Pat. No. 5,786,436 (method ofpreparing inorganic pigment dispersions), U.S. Pat. No. 5,961,710(inorganic pigment granules process for their production and use), U.S.Pat. No. 5,968,248 (heat resistant inorganic pigment), U.S. Pat. No.6,197,879 (method of preparing inorganic pigment dispersions), and thelike. The entire disclosure of each of these United States patents ishereby incorporated by reference into this specification.

The inorganic pigment used preferably has a particle size distributionsuch that at least about 95 weight percent of its particles arepreferably smaller than 1 micron. In one embodiment, at least 95 weightpercent of the particles of inorganic pigment have a size within therange of from about 0.1 to about 0.7 microns. In another embodiment, atleast 95 weight percent of the pigment particles have a particle sizewithin the range of from about 0.1 to about 0.5 microns.

In one preferred embodiment, the inorganic pigment is carbon black. Asis known to those skilled in the art, carbon black is an amorphouspowdered carbon resulting from the incomplete combustion of a gas,usually deposited by contact of the flame on a metallic surface, butalso made by the incomplete combustion of gas in a chamber. Referencemay be had, e.g., to pages 143-145 of George S. Brady's “MaterialsHandbook,” Thirteenth Edition (McGraw-Hill, Inc., New York, N.Y., 1991).Reference may also be had, e.g., to U.S. Pat. No. 3,519,452 (sulfonatedcarbon black pigments), U.S. Pat. No. 3,725,103 (carbon black pigments),U.S. Pat. No. 3,799,788 (carbon black pigments), U.S. Pat. No. 3,836,378(production of composite pigments or iron oxide and carbon black), U.S.Pat. No. 3,973,983 (carbon black pigments and rubber compositionscontaining the same), U.S. Pat. No. 4,076,551 (carbon black-containingpigments and process for their preparation), U.S. Pat. No. 4,170,486(carbon black compositions and black-pigmented compositions containingsame), U.S. Pat. No. 4,366,138 (carbon black useful for pigment forblack lacquers), U.S. Pat. No. 4,379,871 (process for the production ofcarbon black containing pigment synthetic resin concentrates), U.S. Pat.No. 5,286,291 (pigments containing carbon black), and the like. Theentire disclosure of each of these United States patents is herebyincorporated by reference into this specification.

In one embodiment, a mixture of carbon black and a resin is prepared byconventional means. The resin used is preferably a synthetic resin that,e.g., is a film-forming synthetic resin; and processes for preparingmixtures of such synthetic resin and carbon black are well known.Reference may be had, e.g., to U.S. Pat. No. 3,557,040 (process forpreparing a carbon black-synthetic resin composition), U.S. Pat. No.3,563,916 (carbon-black-synthetic resins electro-conductivecomposition), U.S. Pat. No. 3,833,541 (molding powder of aggregatescontaining carbon black embedded in matrix of vinyl chloride-acetateresin and heat stabilizer), U.S. Pat. No. 3,925,301 (process for thecontinuous production of carbon black-synthetic resin concentrates),U.S. Pat. No. 4,379,871 (process for the production of carbon blackcontaining pigment-synthetic resin concentrates), U.S. Pat. No.4,442,160 (electrostatic recording medium having an electricallyconductive layer containing pre-dispersed electrically conductive carbonblack and polyurethane binder resin), U.S. Pat. No. 4,683,158 (carpethaving bottom portions of pile covered with carbon back containingresin), U.S. Pat. No. 4,734,450 (polypropylene-based resin compositioncontaining an inorganic filer and 0.01 to 0.6 weight percent of carbonblack), U.S. Pat. No. 5,041,473 (process for producing carbon blackfilled polyethylene resins), U.S. Pat. No. 5,207,949 (highly conductivepolyoxymethylene resin composition containing carbon black), and thelike. The entire disclosure of each of these United States patents ishereby incorporated by reference into this specification.

The tinting agent preferably contains from about 10 to about 35 weightpercent of pigment (such as, e.g., carbon black), and from about 90 toabout 65 weight percent of resin, both by combined weight of pigment andresin. In one embodiment, the tinting agent contains from about 10 toabout 20 weight percent of pigment and from about 90 to about 80 weightpercent of resin.

In one embodiment, the tinting agent is made from a water soluble resinand carbon black by the process depicted in FIG. 3. Referring to FIG. 3,and to the process 200 depicted therein, in step 202 the pH of the waterused in the process is adjusted so that it is from about 10 to about 11and, more preferably about 10.3 to about 10.7. A sufficient amount ofwater may be charged to a container (such as, e.g., a beaker) so thatwhen the resin is thereafter charged to the container it will containfrom about 20 to about 50 parts of resin, by total weight of resin andwater.

One may add ammonia to the water to adjust its pH. Alternatively, oradditionally, one may add other pH increasing agents such as, e.g.,sodium hydroxide, potassium hydroxide, etc.

Once the pH of the water has been suitably adjusted, one may chargewater-soluble resin to the water. One may use one or more of thewater-soluble resins known to those skilled in the art. Reference may behad, e.g., to U.S. Pat. No. 3,420,231 (inversely water soluble resin),U.S. Pat. No. 3,490,039 (water soluble resin trunk polymer), U.S. Pat.No. 3,901,836 (rust preventative coating for metallic surfacesconsisting of water-soluble resin and sodium benzoate-potassiumtripolyphosphate rust inhibitor), U.S. Pat. No. 3,947,246 (process forproducing spotted dyeings with pastes containing water-soluble resin orwax and particulate dyestuff), U.S. Pat. No. 4,017,433 (pitch watersoluble resin and alkyd resin as binder composition for refractoryparticles), 4 m179,417 (composition for water-based paint comprisingwater-soluble resin and water-dispersible polymer), U.S. Pat. No.5,034,498 (method and apparatus for producing water-soluble resin andresin product made by that method), U.S. Pat. No. 5,039,787 (method forproduction of cationic water-soluble resin and water-treating agentcontaining said resin based on imine modified polyethylene glycolhalohydrin ethers), U.S. Pat. No. 5,041,252 (nonwoven fabric ofwater-soluble resin fibers), U.S. Pat. No. 5,207,964 (method formanufacturing a plastic hollow product using water soluble resin), U.S.Pat. No. 5,264,318 (positive type photosensitive composition developablewith water comprising a photocrosslinking agent, a water-soluble resin,and an aqueous synthetic resin), U.S. Pat. No. 5,349,003 (aqueousfluorine-containing polymer dispersion and aqueous dispersion containingfluorine containing polymer and water-soluble resin and/or waterdispersible resin), U.S. Pat. No. 5,360,860 (water-soluble resinemulsion and process for preparation thereof), U.S. Pat. No. 5,913,972(aqueous pigment dispersion, water-soluble resin, production process ofthe resin, and equipment suitable for use with the dispersion), U.S.Pat. No. 6,555,607 (water-soluble resin composition), U.S. Pat. No.6,608,121 (water soluble resin composition and water-soluble film), U.S.Pat. No. 6,613,388 (method of producing a recording sheet containinginorganic particulates and a water-soluble resin), U.S. Pat. No.6,720,367 (ink composition comprising cationic, water-soluble resin),U.S. Pat. No. 6,809,128 (ink composition comprising cationicwater-soluble resin and ink set), U.S. Pat. No. 7,937,956 (water-solubleresin, process for its production, and water-soluble resin composition),and the like. The entire disclosure of each of these United Statespatents is hereby incorporated by reference into this specification.

In one embodiment, the water-soluble resin is curable and, after beingso cured, becomes water insoluble. Curable resins and well known tothose skilled in the art. Reference may be had, e.g., to U.S. Pat. No.3,373,812 (method of permeably consolidating incompetent sands with aheat-curable resin), U.S. Pat. No. 4,087,479 (heat curable resincompositions for powder paints), U.S. Pat. No. 4,242,475 (process forproducing novel curable resin capable of being cured by the exposure toheat or radiation and curable coating composition containing saidcurable resin), U.S. Pat. No. 4,528,363 (heat-curable resin coatingcomposition), U.S. Pat. No. 4,861,672 (one-can heat-curable resincompositions), U.S. Pat. No. 4,940,740 (single phase toughenedheat-curable resin compositions), U.S. Pat. No. 4,985,509 (heat curableresin composition), U.S. Pat. No. 4,996,267 (heat-curable resin mixtureof monocyanate, polycyanate, and reactive thermoplastic), U.S. Pat. No.5,326,827 (heat-curable resin composition containing acrylic polymerhaving alicyclic epoxide functions), U.S. Pat. No. 5,747,615(slurry-mixed heat-curable resin systems having superior tack anddrape), U.S. Pat. No. 7,098,258 (heat-curable resin composition), andthe like. The entire disclosure of each of these United States patentsis hereby incorporated by reference into this specification.

In one embodiment, the resin used is an ester of pentaerythritol androsin. These esters are well known and are disclosed, e.g., in U.S. Pat.No. 4,548,746, the entire disclosure of which is hereby incorporated byreference into this specification. This patent claims (in claim 1thereof) “A process for esterifying rosin with at least an equivalent ofpentaerythritol which comprises heating the rosin and pentaerythritol inthe presence of phosphinic acid catalyst.” This patent discloses that:“Rosin is mainly a mixture of C20, fused-ring, monocarboxylic acids,typified by levopimaric and abietic acids, both of which are susceptibleto numerous chemical transformations. The rosins to which this inventionrelates include gum rosin, wood rosin and tall oil rosin.”

U.S. Pat. No. 4,548,746 also discloses that: “The natural separation andgradual conversion of some of the hydrophilic components of sap andrelated plant fluids from the cambium layer of a tree into increasinglyhydrophobic solids are the generic process of forming diverse gums,resins and waxes. The oleoresin intermediate in this process is typifiedin pine gum, which flows from hacks on the trunks of southern yellowpine in southeastern United States, in France, and in other countries.Pine gum contains about 80% (gum) rosin and about 20% turpentine.”

U.S. Pat. No. 4,548,746 also discloses that: “Resinification fromoleoresin can result from either natural evaporation of oil from anextrudate or slow collection in ducts in sapwood and heartwood. Pinusstumps are valuable enough to be harvested, chipped, and extracted withhexane or higher-boiling paraffins to yield wood rosin, wood turpentine,and other terpene-related compounds by fractional distillation. In thekraft, i.e., sulfate, pulping process for making paper, pinewood isdigested with alkali producing crude tall oil and crude sulfateturpentine as by-products. Fractionation of the crude tall oil yieldstall oil rosin and fatty acids.”

U.S. Pat. No. 4,548,746 also discloses that: “The chemicaltransformation of gum, wood, and tall oil rosin which relates to thisinvention is esterification. The beneficial product characteristicsprovided by rosin esterification for various applications have led tothe development of many esterification procedures, particularlytreatments with polyhydric alcohols. U.S. Pat. Nos. 2,369,125, 2,590,910and 2,572,086 teach rosin esterification with glycerol andpentaerythritol, among other polyhydric alcohols, usually preceded by arosin disproportionation step.”

U.S. Pat. No. 4,548,746 also discloses that: “It is generally known inthe art that a significant disadvantage of pentaerythritolesterification of tall oil rosin as compared with glycerolesterification is the deterioration of rosin color in the product of theformer process. For a tall oil rosin with a starting color of 8 on theGardner scale, a pentaerythritol ester would have a color of 13-18 whilea glycerol ester would have a color of 8-9. Also, extremely longreaction times are required to make the tall oil rosin-pentaerythritolesters (up to 30-48 hours) as compared to making tall oil rosin-glycerolesters under identical conditions (10-12 hours). It was this concernwhich led to the discovery of the invention process hereinafterclaimed.”

U.S. Pat. No. 4,548,746 also discloses that: “U.S. Pat. Nos. 3,780,012and 3,780,013 acknowledge that tall oil rosin, as opposed to gum or woodrosin, darkens significantly upon pentaerythritol esterification andpropose alternative solutions. U.S. Pat. No. 3,780,012 teachespretreating the rosin with paraformaldehyde followed by distillationprior to the esterification reaction. U.S. Pat. No. 3,780,013 teachesthe incremental addition of a phenol sulfide compound during theesterification. The color of the product of these procedures was claimedto be an M (U.S.D.A. scale), equal to 11-12 on the Gardner scale. Also,the patents' examples employed a 20% equivalent excess ofpentaerythritol.”

U.S. Pat. No. 4,548,746 also discloses that: “U.S. Pat. No. 2,729,660also acknowledges the darkening effect which common esterificationcatalysts such as strong acids cause on the product duringesterification. The patent teaches the use of 0.5 to 5% of either thealiphatic or aromatic esters of phosphorous acid as a catalyst for theesterification of higher fatty acids or rosin acids, or mixturesthereof. In addition to avoiding appreciable color formation during theesterification, a reduction in reaction time is noted. A distinctdisadvantage of this process is the dissociation, during esterification,of the alcohol used to make the phosphite ester catalyst resulting in adisagreeable odor.”

U.S. Pat. No. 4,548,746 also discloses that: “U.S. Pat. No. 4,172,070teaches employing arylsulfonic acid in place of the traditional basicesterification catalysts, such as calcium oxide, to reduce the time fortall oil rosin-pentaerythritol esterification to obtain a rosin ester ofimproved oxygen stability, color and softening point. This work isconfounded, however, by the unusually large amount of pentaerythritolused (35% equivalent excess) which by itself would markedly increase therate of acid number drop. Products with Ring and Ball softening pointsof 77° C. to 86.5° C. were obtained. Normal commercial pentaerythritolesters of rosins soften between 95° C. and 105° C.”

In one preferred embodiment, the resin used in a fumaric modifiedpentarythritol ester identified by Chemical Abstracts Registry number68152-57-8 and sold as “Filtrez 521” by Hexion Specialty Chemicals Inc.of 1202 East Parker Street, Baxley, Ga. 31513.

Referring again to FIG. 3, and to step 204 thereof, the water-solublecurable resin is mixed with the water until it is completely dissolved.In one embodiment, from about 20 to about 50 parts of resin are mixedwith about 80 to about 50 parts of water, both by weight. In anotherembodiment, from about 25 to about 40 parts of resin are mixed with fromabout 785 to about 60 parts of water. In yet another embodiment, about30 parts of resin are mixed with about 70 parts of water.

The water used is preferably at ambient temperature, and the resin isadded to the water, with stirring, and blended over a suitable periodof, e.g., from about 10 to about 15 minutes. Thereafter, the solutionthis produced is mixed with the pigment to form a slurry. The pigment(such as, e.g., carbon black) is preferably slowly added and blendedwith the solution in step 206 until a substantially homogeneous slurryhas been produced.

The substantially homogeneous slurry produced in step 206 is thenblended with amine-coated headlap granules prepared in step 203.

In one embodiment, the amine-coated headlap granules are prepared inaccordance with the process described elsewhere in this specification inwhich one or more of the amines described is sprayed onto the limestonegranules as such granules are being transferred through a blendingscrew. However, in this embodiment, wherein the amine-coated headlapgranules are to be mixed with the slurry, it is preferred not to use oilto during the coating of such amines onto the limestone granules.

Referring again to FIG. 3, and to the preferred embodiment depictedtherein, in step 207 the amine-coated limestone granules are coated withthe slurry produced in step 206. It is preferred to coat theamine-coated limestone granules with slurry in the same manner(described elsewhere in this specification) in which the uncoatedlimestone granules were coated with amine, viz.—spraying the coatingagent (in this case the slurry, in the prior case the amine) onto thelimestone granules as such granules are being transferred through ablending screw. Alternatively, or additionally, other conventionalcoating processes may be used; thus, e.g., a nebulizing spray mixer maybe used.

The slurry-coated and amine-coated limestone granules are then heattreated in step 209, wherein they are subjected to a temperature of 130degrees Centigrade for at least 15 minutes to drive off the water and tocure the tinting agent slurry. The product thus produced issubstantially water insoluble.

The solubility of the product produced in step 209 of FIG. 3 may betested in accordance with a process in which 100 grams of such productare disposed in a 500 milliliter beaker to which 375 milliliters ofwater are then added, and the material is mixed and thereafter boiledfor 2 hours. Thereafter, the material is inspected to determine theextent to which, if any, the tinting agent has been removed from thelimestone granules. Any of the ink that has separated from the particleswill produce turbidity in the water and/or floating black particles inthe water and/or material stuck to the surface(s) of the beaker. It ispreferred that less than about 5 weight percent (and, more preferably,less than about 1 weight percent) of the tinting agent be removed fromthe coated headlap granules by this test.Another Preferred Process of the Invention

In one embodiment, the roofing granules of this invention are made insubstantial accordance with the procedure described with reference toFIGS. 1 and 3, with several modifications.

In the first place, two mixers are used (see, e.g., “mixer 36” and“mixer 38” depicted in FIG. 1). It is preferred to charge the particlesfrom air flow separator 30 to mixer 36 via line 34 and, while suchparticles are in such mixer, mix them with the pigment and bindermixture described in this specification. In this embodiment, theantistrip agent and/or the oil are not charged to mixer 36 but arethereafter charged to mixer 38. Thus, the difference in this newembodiment is that the pigment and binder mixture are charged and mixedwith the particles prior to the time they are contacted with either theantistrip agent and/or the oil.

In one aspect of this embodiment, the mixer 36 is heated such that,during the mixing of the particles with the pigment/binder mixture, suchparticles are preferably heated to a temperature of at least about 130degrees Celsius for at least about 15 minutes. In one aspect of thisembodiment, such particles are heated to a temperature of at least about130 degrees Celsius for at least about 22 minutes.

In this embodiment, one may use the same pigments and/or binders as hasbeen described elsewhere in this specification. Alternatively, one mayreplace some or all of the binder described hereinbefore with a filmforming binder.

As is known to those skilled in the art, a film forming binder is amaterial that forms a polymeric surface which encapsulates the particleswith which it is contact. Reference may be had, e.g., to U.S. Pat. No.5,079,037 (resistive films comprising resistive short fibers ininsulating film forming binder), U.S. Pat. No. 5,516,458 (coatingcomposition containing film forming binder), and U.S. Pat. No. 6,096,835(coating composition containing film forming binder). Reference also maybe had to published United States patent applications US2003/013050(coating composition containing polythiophene and film-forming binder)and US2005/0029496. The entire disclosure of each of such United Statespatents and published United States patent applications is herebyincorporated by reference into this specification.

In one embodiment, the mineral composition of this invention is coatedwith a film forming binder containing a pigment. The desired effect ofthis pigment-binder system is to coat the exposed surface of thegranules where as the cured coating surface is not readily stripped awayby additional processing or by heating during processing.

When such film forming binder is used, it is preferred that to mix suchbinder with the pigment described elsewhere in this specification toproduce a mixture that preferably comprises from about 15 to about 20weight percent of such binder, from about 15 to about 20 weight percentof such pigment, and one or more solvents. The solvent used ispreferably an aqueous solvent that comprises water.

In one embodiment, a pigment is used to produces a black color withcertain L*a*b* values. These L*a*b* values may be measured using the“Lab color space system.”

As is known to those skilled in the art, “Lab” is the abbreviated nameof two different color spaces, the best known of which is “CIELAB” (alsoreferred to as “CIE 1976 L*a*b*”). Both of these spaces are derived fromthe “master” space, CIE 1931 color space. CIELAB is calculated usingcube roots, and Hunter Lab is calculated using square roots. Referencemay be had, e.g. to a web site appearing athttp://en.wikipedia.org/wiki/Lab_color_space.

CIELAB has been widely described in the patent literature. Thus, e.g.,it is described in both the claims and the disclosures of U.S. Pat. No.5,751,484 (coatings on glass), U.S. Pat. No. 5,932,502 (lowtransmittance glass), U.S. Pat. No. 5,512,521 (cobalt-free, black, dualpurpose enamel glass), U.S. Pat. No. 6,629,792 (thermal transfer ribbonwith a frosting ink layer), U.S. Pat. No. 6,722,271 (ceramic decalassembly), U.S. Pat. No. 6,796,733, etc.; the disclosure of each ofthese United States patents is hereby incorporated by reference intothis specification.

In one aspect of this embodiment, the pigment used in applicants'process is carbon black, and the L* number obtained for the pigmentedmaterial obtained is less than 30. In one aspect of this embodiment, theL* value obtained is from about 15 to about 30.

It is preferred that the Hunter a* and be values be less than about 5and, preferably, less than about 2. In one embodiment, the Hunter a*value is from about −5 to +5, and the Hunter b* value of from about −5to about 5.

Referring again to FIG. 1, the binder, pigment, and water are preferablypresent in the form of an aqueous slurry, and such slurry is preferablysprayed onto the particles in mixer 36. In one embodiment, the mixer 36preferably is comprised of nozzles through which the slurry may besprayed as the particles are being tumbled.

During the tumbling/spraying process, it is preferred to subject theparticles being so treated to a temperature of at least 130 degreesCelsius. It is also preferred to conduct the spraying operation so thata substantially homogeneous mixture of coated particles is produced. Inone embodiment, the spraying, tumbling, and heating operations occursimultaneously for a period of at least 15 minutes.

In one embodiment, the coating produced on the particles, after drying,is applied at a coating weight of from about 0.25 to about 0.4 weightpercent, by weight of uncoated particles.

Referring to FIG. 1, after the coated particles are prepared in mixer36, they are then fed via line 40 to mixer 38, wherein the antistripagent and/or the oil may be added in the manner described elsewhere inthis specification. Thereafter, the treated particles may be fed vialine 44 to mass flow silo 46.

The particles conveyed to mass flow silo 46 are suitable for use asheadlap granules. Additionally, because of their low translucency andtheir optical properties, they may also be used as prime granules. As isknown to those skilled in the art, “Often, in the manufacture ofshingles, at least two types of granules are employed: 1) headlapgranules which are granules of relatively low cost for portions of theshingle which are to be covered up; and 2) prime granules which aregranules of relatively higher cost and are applied to the portions ofthe shingle which will be exposed on the roof. It is to be understoodthat the term “prime” granules generally includes both highlightedcolored blend drop granules and background granules.” This quote istaken from published United States patent application US2007/0082126,the entire disclosure of which is hereby incorporated by reference intothis specification.

In one embodiment, the coated particles of this invention are comprisedof a multiplicity of crystallites that, when contacted with daylight,produce electromagnetic energy that is lethal to algae. In one aspect ofthis embodiment, such crystallites are comprised or consist essentiallyof inorganic material.

FIG. 5 is a schematic diagram of an asphalt shingle 500 made inaccordance with the procedure described elsewhere in this specification.The headlap particles 502 made in accordance with the process of thisinvention are disposed within an asphalt material 504 that, in oneembodiment is a stabilized asphalt.

Referring to FIG. 5, it will be seen that the headlap particles 502 arepreferably not spherical, i.e., their aspect ratios (the ratio of thelargest axis of the particle to the smallest axis) is greater than 1.0.In general, the aspect ratio of the headlap particles is from about 1.4to about 2.0.

Referring again to FIG. 5, it will be seen that, in the embodimentdepicted, the headlap particles are not homogeneous, i.e., different ofthe particles 502 have different sizes and/or shapes. Furthermore,different of the particles 502 are disposed within the asphalt 504 todifferent depths.

In the embodiment depicted in FIG. 5, the asphalt 504 is disposed over aFiberglass base 506 that is contiguous with both the top layer ofasphalt 504 and the bottom layer of asphalt 508. A bottom backsurfacinglayer 510 is contiguous with the bottom layer of asphalt 508.

While preferred embodiments of the invention have been shown anddescribed, modifications thereof can be made by one skilled in the artwithout departing from the scope of and the spirit of the invention. Theembodiments described herein are exemplary and not limiting. Manyvariations thereof are possible and are within the scope of theinvention

We claim:
 1. A shingle assembly comprised of a fiber mat and an asphaltic coating material, wherein said asphaltic coating material is comprised of asphalt, a mineral filler disposed within said asphaltic coating material, and coated roofing granules embedded within said asphaltic coating material, wherein said coated roofing granules are comprised of limestone particles that have a hardgrove grindability index of less than 70, and wherein said coated roofing granules are coated with oil.
 2. The shingle assembly as recited in claim 1, wherein said limestone particles contain at least about 60 weight percent of calcium carbonate.
 3. The shingle assembly as recited in claim 1, wherein said limestone particles contain at least about 70 weight percent of calcium carbonate.
 4. The shingle assembly as recited in claim 1, wherein said limestone particles contain at least about 80 weight percent of calcium carbonate.
 5. The shingle assembly as recited in claim 1, wherein said limestone particles contain at least about 90 weight percent of calcium carbonate.
 6. The shingle assembly as recited in claim 1, wherein said asphaltic coating material is comprised of at least about 65 weight percent of said mineral filler.
 7. The shingle assembly as recited in claim 6, wherein said mineral filler is limestone filler.
 8. The shingle assembly as recited in claim 1, wherein said coated roofing granules are comprised of limestone particles with a hardgrove grindability index of less than about
 68. 9. The shingle assembly as recited in claim 1, wherein said coated roofing granules are comprised of limestone particles with a hardgrove grindability index of less than about
 60. 10. The shingle assembly as recited in claim 1, wherein said coated roofing granules are comprised of limestone particles with a hardgrove grindability index of from about 55 to about
 58. 11. The shingle assembly as recited in claim 1, wherein said coated roofing granules are comprised of particles of dolomitic limestone.
 12. The shingle assembly as recited in claim 1, wherein said oil is naphthenic mineral oil.
 13. The shingle assembly as recited in claim 1, wherein said oil is a hydrocarbon oil.
 14. The shingle assembly as recited in claim 1, wherein said coated roofing granules are comprised of a coating that has a thickness of from about 200 to about 2000 nanometers.
 15. The shingle assembly as recited in claim 1, wherein said coated roofing granules are comprised of a coating that has a thickness of from about 300 to about 1200 nanometers.
 16. The shingle assembly as recited in claim 1, wherein said coated roofing granules are comprised of from about 0.0025 to about 0.0005 gallons of said oil for each pound of said limestone particles.
 17. The shingle assembly as recited in claim 1, wherein said coated roofing granules have a hydrophobicity of less than 3.0 percent.
 18. The shingle assembly as recited in claim 1, wherein said coated roofing granules have a hydrophobicity of less than 2.5 percent.
 19. The shingle assembly as recited in claim 1, wherein said coated roofing granules have a hydrophobicity of less than 2.0 percent.
 20. The shingle assembly as recited in claim 1, wherein said coated roofing granules have a hydrophobicity of less than 1.5 percent.
 21. The shingle assembly as recited in claim 1, wherein said coated roofing granules have a Moh's hardness of from about 2.5 to about 3.5.
 22. The shingle assembly as recited in claim 1, wherein said coated roofing granules have a Moh's hardness of from about 2.9 to about 3.1.
 23. The shingle assembly as recited in claim 1, wherein said coated roofing granules have a pH of from about 8 to about
 11. 24. The shingle assembly as recited in claim 1, wherein said coated roofing granules have a pH of from about 9 to about
 11. 